Information
-
Patent Grant
-
6470848
-
Patent Number
6,470,848
-
Date Filed
Wednesday, May 23, 200123 years ago
-
Date Issued
Tuesday, October 29, 200221 years ago
-
Inventors
-
Original Assignees
-
Examiners
Agents
-
CPC
-
US Classifications
Field of Search
US
- 123 198 E
- 123 195 C
- 123 195 A
- 123 18446
-
International Classifications
-
Abstract
A fuel tank-mounting structure for a portable power working machine, which has an internal combustion engine as a power source and a fuel tank received in a tank housing portion defined in a two-piece cover housing of the power working machine, includes cushioning members supporting the fuel tank in the tank housing portion of the two-piece cover housing. The cushioning members are interposed in spaces between the tank housing portion and all faces of the fuel tank, namely, the front and rear end faces, the right and left side faces, and the top and bottom faces of the fuel tank. The cushioning members prevent the vibration of the internal combustion engine from being easily transmitted to the fuel tank, thereby avoiding the generation of bubbles in the fuel as well as damage to the fuel tank, and also reduce the manufacturing cost of the fuel tank-mounting structure.
Description
BACKGROUND OF THE INVENTION
The present invention relates to a fuel tank-mounting structure for a portable power working machine, such as a leaf blower, a sprayer, and the like, wherein a fuel tank is received in a tank housing portion defined by a two-piece cover housing of the power working machine.
FIG. 6
is an exploded perspective view of a previously known leaf blower, representing one example of a portable power working machine provided with the aforementioned fuel tank-mounting structure. In the assembled state, the leaf blower of
FIG. 6
is similar in external appearance to the leaf blower shown in
FIG. 1
, which shows one embodiment of the present invention as described hereinafter.
The conventional leaf blower
5
shown in
FIG. 6
is provided with right and left cover housings
12
and
11
constituting a two-piece structure, in which a centrifugal air blower
20
and an internal combustion engine (a small air-cooled two-stroke gasoline engine)
30
for rotatably driving the air blower
20
are housed and held in place. External air is inducted from an intake port (not shown) provided on the left side of the left cover housing
11
and accelerated in a volute case
22
provided integrally with the left cover housing
11
. The accelerated air is discharged from an exhaust nozzle
25
defining the terminal portion (an upper front portion) of the volute case
22
and then ejected out of the leaf blower
5
through a flexible tube or an ejection tube (not shown), to thereby blow fallen leaves and refuse.
On the top of the left cover housing
11
, there is mounted a handle
15
which is provided with a throttle lever
17
for controlling the carburetor throttle valve (not shown) of the internal combustion engine
30
and also with an engine stop switch
18
.
Tank housing portions
42
and
41
(
40
) for housing and retaining a fuel tank
50
′ for the fuel (gasoline) for the internal combustion engine
30
are provided at a lower portion of each of the right and left cover housings
12
and
11
.
The fuel tank
50
′ is a closed container shaped into an elongated (in the longitudinal direction of the cleaner
5
) rectangular parallelopiped and provided at an upper rear portion thereof (proximal side in the drawing) with a fuel-filling port
55
which extends upward and slopes rightward. The fuel tank
50
′ is also provided on the left side of the fuel-filling port
55
thereof with a grommet-attached insertion hole
56
through which a fuel intake pipe, a return pipe and a tank inner pressure-adjusting pipe (not shown) are introduced into the fuel tank
50
′. A bottom V-groove
52
is formed on the underside of the fuel tank
50
′, the bottom V-groove
52
being adapted to be engaged with a ridge-like protrusion
44
that projects upwardly from the bottom face of the left tank housing portion
41
. A sloping recess portion
54
is formed on the upper surface of the fuel tank
50
′, the recess portion
54
being adapted to be engaged with a protrusion (not visible) at the upper left side portion of the fuel tank housing
40
.
The fuel tank
50
′ is provided with anchoring lugs
58
that protrude from a central portion of the front and rear end faces of the fuel tank
50
′, respectively, the anchoring lugs
58
being designed to be fixed, by means of a screw
59
, to columnar mounting portions
60
attached to and protruding from the inner wall of the left tank housing portion
41
, thereby fastening the fuel tank
50
′ to the left tank housing portion
41
.
A tapped hole
47
is formed at each of the ridge-like protrusion
44
and the front and rear upper edge portions of the left tank housing portion
41
. In conformity with these tapped holes
47
formed in the left tank housing portion
41
, the right tank housing portion
42
is also provided at each of three portions thereof with a screw-receiving hole (e.g.,
49
). Therefore, the right and left tank housing portions
42
and
41
can be joined face to face with each other by introducing screws (e.g.,
59
) from the right cover housing
12
side through the screw-receiving holes
49
and by threading the screws
59
into the tapped holes
47
, thereby clamping the right and left cover housings
12
and
11
to each other.
The right cover housing
12
is provided with cut-out portions
37
and
36
for enabling the muffler
32
of the internal combustion engine
30
and a recoil starter
34
(i.e., the handle
34
a
thereof) to extend out of the right cover housing
12
, and also with a semi-cylindrical port
39
for facilitating removing and attaching the cap of the fuel-filling port
55
of the fuel tank
50
′.
In the conventional fuel tank-mounting structure for a portable power working machine of
FIG. 6
, the fuel tank is fastened to the tank housing portion by anchoring lugs provided on the fuel tank by making use of the screws, as described above. The conventional fuel tank-mounting structure, however, has the following problems.
(1) The vibration of the internal combustion engine and/or of the air blower is directly transmitted to the fuel tank, and due to the vibration, bubbles are generated in the fuel in the fuel tank. Bubbles in the fuel supplied to the internal combustion engine can cause the performance of the internal combustion engine to deteriorate;
(2) Since not only the fuel tank but also the tank housing portion are both required to be provided with mounting members (such as the aforementioned anchoring lugs) for fastening the fuel tank, the manufacturing cost of the power machine is increased, and at the same time, the configuration of the fuel tank is restricted by such mounting members; and
(3) Stresses due to the vibrations of the tank are concentrated at the connections of the aforementioned anchoring lugs with the tank body; the concentrated stresses can lead to fracture of the anchoring lugs.
SUMMARY OF THE INVENTION
The present invention has been made to overcome the aforementioned problems, and therefore an object of the present invention is to provide a fuel tank-mounting structure for a portable power working machine, which is capable of preventing the vibration of the internal combustion engine from being easily transmitted to the fuel tank, thereby avoiding possible deterioration in performance of the internal combustion engine due to formation of bubbles in the fuel, preventing possible damage to the fuel tank, and reducing the manufacturing costs of the fuel tank-mounting structure.
With a view to attaining the aforementioned objects, there is provided, according to the present invention, a fuel tank-mounting structure for a portable power working machine having an internal combustion engine as a power source and a fuel tank that is received in a tank housing portion of a two-piece cover housing of the power working machine. According to the invention, the fuel tank is retained in the tank housing portion by being embraced by one or more cushioning members.
In a preferred embodiment of the present invention, the cushioning member(s) is interposed in spaces between the tank housing portion and all faces of the fuel tank, namely, the front and rear end faces, the right and left side faces, and the top and bottom faces of the fuel tank. Advantageously, the cushioning member(s) is immovably sandwiched between the cover housing and the fuel tank.
The fuel tank-mounting structure, according to the present invention, may include a front end portion-sustaining cushioning member of a generally U-shape in cross section and having an inner surface that engages at least three faces of the fuel tank selected from the front end face, the right side face, the left side face, the top face and the bottom face of the fuel tank and a rear end portion-sustaining cushioning member of a generally U-shape in cross section and having an inner surface that engages at least three faces of the fuel tank selected from the rear end face, the right side face, the left side face, the top face and the bottom face of the fuel tank.
In especially preferred embodiments, there are a front end portion-sustaining cushioning member having a generally U-shaped cross section, the inner surface of which contacts four faces of the fuel tank including the front end face, the top face, the bottom face and one of the right side face and the left side face of the fuel tank, a rear end portion-sustaining cushioning member having a generally U-shaped cross section, the inner surface of which contacts four faces of the fuel tank including the rear end face, the top face, the bottom face and said one of the right side face and the left side face of the fuel tank, and a side face-sustaining cushioning member which contacts the other of the right side face and the left side face. With a fuel tank-mounting structure of the present invention, as described immediately above, the fuel tank is retained in the tank housing portion by being embraced not only by a pair of end portion-sustaining cushioning members, each having a generally U-shaped cross section, the inner surface of each of which engages four faces constituting the front or rear end portions of the fuel tank but excluding one of the right and left side end faces, but also by a side face-sustaining cushioning member, which engages the other of the right and left side faces. In other words, the cushioning members are respectively interposed in spaces between the tank housing portion and all faces of the fuel tank, i.e., the front and rear end faces, the right and left side faces, and the top and bottom faces of the fuel tank, and at the same time, the cushioning members are immovably sandwiched between the cover housings and the fuel tank. Therefore, the fuel tank is sustained in the tank housing portion in such a manner that the fuel tank is “floated” away from the inner surfaces (all inner surfaces) of the tank housing portion by the cushioning members.
The fuel tank-mounting structure according to the present invention reduces the transmission of vibrations of the internal combustion engine or of the air blower to the fuel tank, thereby making it possible to inhibit the generation of bubbles in the fuel and preventing deterioration in performance of the engine. Furthermore, since the mounting members (such as the aforementioned anchoring lugs) and screws for fastening the fuel tank are no longer required to be employed, the configuration of the fuel tank can be selected relatively freely, and at the same time, the manufacturing cost of the power machine can be reduced. Additionally, since the fuel tank is embraced by cushioning members, damage to the fuel tank is hardly possible.
The cushioning members should preferably be manufactured somewhat larger in size than the fuel tank housing portions of the cover housings so as to permit the cushioning members to be slightly compressed between the fuel tank and the cover housings as the cushioning members are installed together with the fuel tank in the tank housing portion. Further, if the fuel tank is made of a synthetic resin having a suitable degree of an oil-swelling property, such as polyethylene, the fuel tank swells with time, thereby making it possible to maintain the tightness in retention of the fuel tank even if the cushioning members lose some of their initial compression as originally installed. Therefore, even if fuel is spilled on the occasion of filling the tank with fuel, the spilled fuel can be prevented from entering into the interface between the fuel tank and cushioning members, and can be simply allowed to fall and discharge through an opening formed at the bottom of the tank housing portion.
Further, if engine cooling air is inducted from the opening formed at the bottom of the tank housing portion and flows along portions of the side walls of the fuel tank, the fuel tank can be cooled by the cooling air, thereby making it possible to maintain the temperature of the fuel at a suitably low degree.
For a better understanding of the present invention and the advantages thereof, an embodiment of the fuel tank-mounting structure according to the present invention is described below with reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
FIG. 1
is a perspective view illustrating a leaf blower representing one example of a portable power working machine provided with a fuel tank-mounting structure according to the present invention;
FIG. 2
is an exploded perspective view of the leaf blower shown in
FIG. 1
;
FIG. 3
is an enlarged perspective view illustrating the arrangement of cushioning members relative to a fuel tank in the leaf blower shown in
FIG. 1
;
FIG. 4
is a cross sectional view taken along the line IV—IV in
FIG. 1
;
FIG. 5
is a cross sectional view taken along the line V—V in
FIG. 1
; and
FIG. 6
is an exploded perspective view illustrating a leaf blower representing one example of a portable power working machine provided with a fuel tank-mounting structure according to the prior art.
DETAILED DESCRIPTION OF THE INVENTION
Referring to
FIGS. 1 and 2
, the same components as those of the conventional leaf blower
5
shown in
FIG. 6
are identified by the same reference numbers as indicated in
FIG. 6. A
leaf blower
1
according to the embodiment has right and left cover housings
12
and
11
constituting a two-piece structure, in which a centrifugal air blower
20
and an internal combustion engine (a small air-cooled two-stroke gasoline engine)
30
for rotatably driving the centrifugal air blower
20
are housed and held in place. In this case, the external air is inducted from an intake port (not shown) provided on the left side of the left cover housing
11
and accelerated in a volute case
22
that is unitary with the left cover housing
11
. The accelerated air is discharged from an exhaust nozzle
25
defining the terminal portion (an upper front portion) of the volute case
22
and then ejected out of the cleaner
5
through a flexible tube or an ejection tube (not shown), to thereby blow fallen leaves and refuse.
On the top of the left cover housing
11
, there is mounted a handle
15
which is provided with a throttle lever
17
for controlling the carburetor throttle valve (not shown) of the internal combustion engine
30
and also with an engine stop switch
18
.
Further, tank housing portions
42
and
41
(
40
) for housing and retaining a fuel tank
50
for storing fuel (gasoline) for the internal combustion engine
30
are provided at a lower portion of each of the right and left cover housings
12
and
11
. In this case, the fuel tank
50
is formed of polyethylene having a suitable degree of oil-swelling property.
The fuel tank
50
is formed of a closed container shaped into an elongated (in the longitudinal direction of the leaf blower
1
) rectangular parallelopiped and provided at an upper rear portion
50
B thereof (proximal side in the drawing) with a fuel-filling port
55
, which protrudes upwardly and is inclined rightwardly. The fuel tank
50
is also provided on the left side of the fuel-filling port
55
thereof with a grommet-attached insertion hole
56
through which a fuel intake pipe, a return pipe and a tank inner pressure-adjusting pipe (not shown) are permitted to be introduced into the fuel tank
50
. Furthermore, a bottom V-groove
52
is formed on the underside of the fuel tank
50
, the bottom V-groove
52
being adapted to be engaged with a ridge-like protrusion
44
which projects up from the bottom face of the left tank housing portion
41
. A sloping recess
54
on the upper surface of the fuel tank
50
accepts a complementary protruding surface of the upper left side portion of the fuel tank housing portion
40
.
A tapped hole
47
is formed at each of the ridge-like protrusion
44
and the front and rear upper edge portions of the left tank housing portion
41
. In conformity with these tapped holes
47
formed in the left tank housing portion
41
, the right tank housing portion
42
is also provided at each of three portions thereof with a screw-receiving hole
49
. Therefore, the right and left tank housing portions
42
and
41
can be connected face to face with each other by introducing screws
46
from the right cover housing
12
side into the screw-receiving holes
49
and by threading the screws
46
into the tapped holes
47
, thereby clamping the right and left cover housings
12
and
11
to each other (see also FIGS.
4
and
5
).
The right cover housing
12
is provided with cut-out portions
37
and
36
that permit the muffler
32
of the internal combustion engine
30
and a recoil starter
34
(i.e., the handle
34
a
thereof) to extend out of the right cover housing
12
, and with a semi-cylindrical recess
39
for facilitating removing and installing the cap of the fuel-filling port
55
of the fuel tank
50
.
For the purpose of mounting the fuel tank
50
in the tank housing portion
40
, there are provided, according to the embodiment, a front-end sustaining cushioning member
61
, a rear-end sustaining cushioning member
62
, and a sidewall-contacting cushioning member
63
.
As best shown in
FIGS. 3 and 4
, the front-end sustaining cushioning member
61
is generally U-shaped in cross section as it is viewed in two orthogonal directions (from the side and from the rear) and comprises a front end wall
61
a
, a left side wall
61
b
, a top wall
61
c
and a bottom wall
61
d
, which are designed to contact four faces (excluding the right side face
50
d
) among the five faces constituting the front end portion
50
A of the fuel tank
50
, so that the front-end sustaining cushioning member
61
is adapted to be mounted so as to hold the front end portion
50
A of the fuel tank
50
. The rear-end sustaining cushioning member
62
is also generally U-shaped in cross section as it is viewed in two orthogonal directions (from the side and from the front) and comprises a rear end wall
62
a
, a left side wall
62
b
, a top wall
62
c
and a bottom wall
62
d
which are designed to be contacted with four faces (excluding the right side face
50
d
) among the five faces constituting the rear end portion
50
B of the fuel tank
50
, so that the rear-end sustaining cushioning member
62
is adapted to be mounted so as to hold the rear end portion
50
B of the fuel tank
50
.
The front end wall
61
a
of the front-end sustaining cushioning member
61
as well as the rear end wall
62
a
of the rear-end sustaining cushioning member
62
are made larger in thickness than the other walls, and are respectively provided on the outer wall thereof with rectangular recessed portions
65
which are arranged in two rows and three columns at an upper portion of the outer wall, with rectangular recessed portions
66
which are arranged in one row and three columns at a lower portion of the outer wall, and with an intermediate horizontal groove
67
. Further, the rear-end sustaining cushioning member
62
is provided at the top wall
62
c
thereof with an arch-shaped cut-out portion
64
in order to prevent the top wall
62
c
from interfering with the fuel-filling port
55
.
A side wall-contacting cushioning member
63
is formed of a rectangular plate and is designed to be contacted with a central portion of the right side wall
50
d
of the fuel tank
50
. Further, as clearly seen from
FIG. 5
, the side wall-contacting cushioning member
63
is provided at central upper and lower portions thereof with a pair of circular holes
68
, respectively, for enabling a pair of protrusions
28
of the right tank housing portion
42
(the right cover housing
12
) to be fitted therein (see
FIG. 5
) so as to hold the cushioning member
63
in place.
In the case of the fuel tank-mounting structure of the leaf blower
1
according to the embodiment which is constructed as described above, as shown in
FIGS. 4 and 5
, the fuel tank
50
is designed to be retained in the tank housing portion
40
(
41
,
42
) by being embraced not only by a pair of end portion-sustaining cushioning members
61
and
62
, each having a generally U-shaped cross section, the inner surface of which is designed to be contacted with four faces among five faces constituting each of the front and rear end portions
50
A and
50
B.
In other words, the cushioning members
61
,
62
(i.e., wall portions
61
a
,
62
a
,
61
c
,
62
c
,
61
d
and
62
d
) and
63
are interposed in the spaces Sa, Sb, Sc, Sd, Se and Sf formed between the tank housing portion
40
and all faces of the fuel tank
50
, i.e. the front and rear side faces, the right and left side faces, and the top and bottom faces of the fuel tank
50
. In this case, the cushioning members
61
,
62
and
63
are immovably sandwiched between the cover housings
11
and
12
defining the tank housing portion
40
and the fuel tank
50
. Therefore, the fuel tank
50
is sustained in the tank housing portion
40
in such a manner that the fuel tank
50
is “floated” away from the inner surfaces (all inner surfaces) of the tank housing portion
40
by means of the cushioning members
61
,
62
and
63
.
With the fuel tank-mounting structure constructed as described above, the vibration of the internal combustion engine
30
or of the air blower
20
is attenuated by the cushioning members
61
,
62
and
63
and hence the vibration can be hardly transmitted to the fuel tank
50
, thereby making it possible to inhibit the generation of bubbles of the fuel as well as the deterioration in performance of the engine. Furthermore, since the mounting members (such as the aforementioned anchoring lugs of
FIG. 6
) and screws for fastening the fuel tank are no longer required to be employed, the configuration of the fuel tank can be selected relatively freely, and at the same time, the manufacturing cost of the power machine can be reduced. Additionally, since the fuel tank is embraced by the cushioning members, the fuel tank is well protected from damage.
The cushioning members
61
,
62
and
63
should preferably be manufactured somewhat larger in size than the tank housing portion so as to permit the cushioning members
61
,
62
and
63
to be slightly compressed between the fuel tank
50
and the cover housings
11
and
12
when the cushioning members
61
,
62
and
63
are installed, together with the fuel tank
50
in the tank housing portion
40
. Further, if the fuel tank
50
is made of a synthetic resin having a suitable degree of an oil-swelling property, such as polyethylene, the fuel tank
50
can be suitably swelled with time, thereby making it possible to maintain the tightness in retention of the fuel tank
50
, even if the cushioning members
61
,
62
and
63
lose some of the initial compression. Therefore, even if fuel is spilled out when the tank is being filled, the spilled fuel can be prevented from entering into the interface between the fuel tank
50
and cushioning members
61
,
62
and
63
, and can be simply allowed to fall and discharge through the openings
38
formed at the bottom of the cover housings
11
and
12
.
If engine cooling air is inducted from the openings
38
formed at the bottom of the tank housing portion
40
and flows along portions of the sides of the fuel tank
50
, the fuel tank
50
can be cooled by the cooling air.
Although a preferred embodiment of the present invention has been explained in the foregoing description, it should be understood that the present invention is not limited to these embodiments, but can be varied without departing from the spirit and scope of the invention set forth in the accompanying claims.
As seen from the above explanation, it is possible, with the fuel tank-mounting structure of the present invention, to prevent the vibration of the internal combustion engine from being easily transmitted to the fuel tank, thereby avoiding the deterioration in performance of the engine due to the forming of bubbles in the fuel, preventing damage or breakage of the fuel tank, and reducing the manufacturing cost thereof.
Claims
- 1. A fuel tank-mounting structure for a portable power working machine having an internal combustion engine as a power source and a fuel tank, the fuel tank being received in a tank housing portion defined in a two-piece cover housing of the power working machine, comprising at least one cushioning member supporting the fuel tank in the tank housing portion of the two-piece cover housing,wherein the at least one cushioning member is interposed in spaces between the tank housing portion and all faces of the fuel tank, namely, the front and rear end faces, the right and left side faces, and the top and bottom faces of the fuel tank.
- 2. The fuel tank-mounting structure according to claim 1, wherein the at least one cushioning member is immovably sandwiched between the cover housing and the fuel tank.
- 3. The fuel tank-mounting structure according to claim 1 or 2, wherein said structure comprises a front end portion-sustaining cushioning member of a generally U-shaped in cross section and having an inner surface that engages at least three faces of the fuel tank selected from the group consisting of the front end face, the right side face, the left side face, the top face and the bottom face of the fuel tank and a rear portion-sustaining cushioning member of a generally U-shaped in cross section and having an inner surface that engages at least three faces of the fuel tank selected from the group consisting of the rear end face, the right side face, the left side face, the top face and the bottom face of the fuel tank.
- 4. The fuel tank-mounting structure according to claim 1 or 2, wherein said structure comprises a front end portion-sustaining cushioning member having a generally U-shaped cross section, the inner surface of which contacts four faces of the fuel tank including the front end face, the top face, the bottom face and one of the right side face and the left side face of the fuel tank, a rear end portion-sustaining cushion member having a generally U-shaped cross section, the inner surface of which contacts four faces of the fuel tank including the rear end face, the top face, the bottom face and said one of the right side face and the left side face of the fuel tank, and a side face-sustaining cushioning member which contacts the other of the right side face and the left side face.
Priority Claims (1)
Number |
Date |
Country |
Kind |
2000-153756 |
May 2000 |
JP |
|
US Referenced Citations (5)