U.S. patent application number 12/445340 was filed with the patent office on 2010-04-08 for blower.
This patent application is currently assigned to SHINDAIWA CORPORATION. Invention is credited to Keigo Egawa.
Application Number | 20100086412 12/445340 |
Document ID | / |
Family ID | 39282526 |
Filed Date | 2010-04-08 |
United States Patent
Application |
20100086412 |
Kind Code |
A1 |
Egawa; Keigo |
April 8, 2010 |
BLOWER
Abstract
A blower (1) comprises a blast fan (20) provided within a casing
(10), a driving unit (30) for rotationally driving the blast fan
(20), a dust-proof cover (60) provided so as to cover an air intake
(11) of the casing (10) and a drive stop mechanism (70) for
stopping the driving unit (30). The drive stop mechanism (70)
comprises a depressing lever (72) that depresses a pressure sensor
(71) when it is pressed by a projection (65b) of the dust-proof
cover (60) that is inserted into an attachment hole (12) of the
casing (10) and a control section (73) for stopping the driving
unit (30) when the pressure acting on the pressure sensor (71) from
the depressing lever (72) decreases. This structure allows safety
of the blower to be improved when the dust-proof cover (60) is
removed from the air intake (11) and the air intake (11) is exposed
to the outside because the rotation of the blast fan (20)
automatically stops.
Inventors: |
Egawa; Keigo; (Hiroshima,
JP) |
Correspondence
Address: |
MERCHANT & GOULD PC
P.O. BOX 2903
MINNEAPOLIS
MN
55402-0903
US
|
Assignee: |
SHINDAIWA CORPORATION
Hiroshima-shi ,Hiroshima
JP
|
Family ID: |
39282526 |
Appl. No.: |
12/445340 |
Filed: |
October 13, 2006 |
PCT Filed: |
October 13, 2006 |
PCT NO: |
PCT/JP2006/320477 |
371 Date: |
May 27, 2009 |
Current U.S.
Class: |
417/1 ;
15/405 |
Current CPC
Class: |
F04D 27/008 20130101;
F04D 29/703 20130101; E01H 1/0827 20130101; F04D 25/04 20130101;
E01H 1/0809 20130101; A01G 20/47 20180201 |
Class at
Publication: |
417/1 ;
15/405 |
International
Class: |
A47L 5/24 20060101
A47L005/24; F04B 49/00 20060101 F04B049/00 |
Claims
1. A blower, comprising a blast fan provided within a casing, a
driving unit for rotationally driving the blast fan, a blast duct
for discharging an air flow generated by the rotating blast fan to
an outside, a dust-proof cover provided to cover an air intake
formed in the casing and a drive stop mechanism for stopping the
driving unit, wherein the dust-proof cover is attached to the
casing by inserting a projection provided in the dust-proof cover
into an attachment hole formed in the casing, and wherein the drive
stop mechanism comprises: a pressure sensor provided in the casing;
a depressing lever having a first end in contact with a detecting
part of the pressure sensor and a second end which is disposed in
the attachment hole and is pressed by the projection that is
inserted into the attachment hole so as to have the first end
depresses the detecting part of the pressure sensor; and a control
section for setting up the driving unit into a drivable state if a
pressure applied to the detecting part of the pressure sensor and
for setting up the driving unit into a stop state if the pressure
applied to the detecting part of the pressure sensor decreases.
2. The blower according to claim 1, wherein the depressing lever
has an intermediary portion of the depressing lever exposed to an
the air intake and is formed to have the first end of the
depressing lever presses the detecting part of the pressure sensor
if the intermediate portion of the depressing lever is pressed by a
suction pipe inserted into the air intake.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Technical Field of Invention
[0002] The present invention relates to a blower for sweeping
objects such as dead leaves and sprigs deposited on the ground by
blowing them away and also for cleaning dusts by vacuuming them
up.
[0003] 2. Description of the Related Art
[0004] As a blower for sweeping objects such as dead leaves and
sprigs deposited on the ground by blowing them away, there is one
having a blast fan provided within a casing, an engine for
rotationally driving the blast fan and a blast duct for discharging
an air flow generated by the rotating blast fan to the outside.
[0005] Such a blower is provided with a grip attached to the casing
and an operator can carry around the blower by holding the grip.
Then, the operator can blow and sweep the objects such as dead
leaves and sprigs by discharging the high-speed air flow to the
ground out of an air outlet of a blower pipe coupled with the blast
duct.
[0006] The casing of the blower is provided also with an air intake
for taking fresh air into the casing and the fresh air suctioned
into the casing from the air intake becomes the high-speed air flow
by the rotating blast fan as the fan is rotated.
[0007] The blower constructed as described above may be also
provided with a cylindrical vacuum pipe at the air intake and with
a net-like dust collecting bag at the blast duct to vacuum up and
collect the dusts from a suction mouth of the vacuum pipe as
disclosed in Japanese Patent Application Laid-open No. 2005-163765
for example. Thus, the blower may be utilized also as a vacuum
cleaner.
[0008] It is noted that because the air intake of the blower is
provided with a dust-proof cover to prevent from sucking extraneous
materials, it is necessary to remove the dust-proof cover and to
expose the air intake to the outside in order to attach the vacuum
pipe to the air intake. At this time, there is a problem that the
blower must be handled carefully when the blast fan is rotating
within the casing.
SUMMARY OF THE INVENTION
[0009] In order to deal with the problem of the prior art described
above, the inventor has promoted research and development and has
invented the present invention. That is, one aspect of the
invention is to provide a blower whose safety is improved by
automatically stop rotation of a blast fan when a dust-proof cover
is removed from an air intake and the air intake is exposed to the
outside.
[0010] More specifically, the blower of one aspect of the invention
has the blast fan provided within a casing, a driving unit for
rotationally driving the blast fan, a blast duct for discharging an
air flow generated by the rotating blast fan to the outside, a
dust-proof cover provided so as to cover an air intake formed in
the casing and a drive stop mechanism for stopping the driving
unit. The blower is characterized in that the dust-proof cover is
attached to the casing by inserting a projection provided in the
dust-proof cover into an attachment hole formed in the casing and
that the drive stop mechanism has a pressure sensor provided in the
casing, a depressing lever whose one end contacts with a detecting
part of the pressure sensor and whose other end is disposed in the
attachment hole and one end depresses the detecting part of the
pressure sensor when the other end is pressed by the projection
that is inserted into the attachment hole and a control section for
setting up the driving unit into a drivable state when a pressure
acts on the detecting part of the pressure sensor and for setting
up the driving unit into a stop state when the pressure acting on
the detecting part of the pressure sensor decreases.
[0011] When the dust-proof cover is removed out of the air intake
and when the projection of the dust-proof cover moves in a
direction of being pulled out of the attachment hole of the casing,
the pressure acting on the other end of the depressing lever from
the projection decreases in this arrangement. Due to that, the
pressure acting on the detecting part of the pressure sensor from
one end of the depressing lever also decreases, so that the control
section sets up the driving unit into the stop state.
[0012] Still more, because the control section is arranged so that
it sets up the engine of the driving unit into the haling state
when the pressure acting on the pressure sensor by the depressing
lever decreases, the engine halts when the projection of the
attachment screw of the dust-proof cover is not completely pulled
out, i.e., when the attachment screw of the dust-proof cover is
loosened.
[0013] Thus, the engine is put into the stop state and the blast
fan stops from rotating before the air intake of the casing is
exposed to the outside, so that it is possible to improve the
safety of the blower in opening the dust-proof cover from the air
intake.
[0014] Still more, because the control section changes the driving
states of the engine of the driving unit based on the variation of
the pressure applied to the pressure sensor that varies depending
on whether or not the dust-proof cover is attached, it is readily
possible to change over the driving states of the driving unit.
[0015] Still more, the intermediate portion of the depressing lever
is exposed to the inner peripheral face of the air intake in the
blower described above, so that it is possible to arrange so that
one end of the depressing lever depresses the detecting part of the
pressure sensor when the suction pipe inserted into the air intake
depresses the intermediate portion of the depressing lever.
[0016] Further, because the control section changes the states of
the driving unit from the stop state to the drivable state when the
vacuum pipe is attached to the air intake and the depressing lever
depresses the detecting part of the pressure sensor, it is thus
possible to change over the driving states of the driving unit with
this arrangement.
[0017] The various aspects and effects of the invention described
above as well as other effects and features thereof will be more
clearly understood by the following detailed explanation of
illustrative and nonrestrictive embodiments of the invention made
with reference to the appended drawings.
BRIEF DESCRIPTION OF DRAWINGS
[0018] FIG. 1 shows a blower of a present embodiment and is a
perspective view seen from a front side thereof in a state in which
a dust-proof cover is closed.
[0019] FIG. 2 shows the blower of the present embodiment and is a
perspective view seen from the front side thereof in a state in
which the dust-proof cover is opened.
[0020] FIG. 3A and FIG. 3B show a drive stop mechanism of the
blower of the embodiment, wherein FIG. 3A is a transverse section
view showing a state in which the dust-proof cover is closed and
FIG. 3B shows a transverse section view showing a state in which
the dust-proof cover is opened.
[0021] FIG. 4 is a diagrammatic structural view showing the drive
stop mechanism of the blower of the embodiment.
[0022] FIG. 5 is a perspective view showing the blower of the
embodiment seen from the front side thereof in a state in which a
vacuum pipe is attached.
[0023] FIG. 6 is a transverse section view showing the drive stop
mechanism of the blower of the embodiment in a state in which the
vacuum pipe is attached.
DETAILED DESCRIPTION OF THE INVENTION
[0024] Embodiments for carrying out the invention will be explained
in detail below with reference to the drawings. It is noted that
front and back and right and left directions in the following
explanation are directions seen from an operator in using a blower
and correspond to front and back and right and left directions
shown in each drawing.
[Whole Structure of Blower]
[0025] The blower 1 of the present embodiment shown in FIG. 1 is a
power blower for sweeping objects such as dead leaves and sprigs
deposited on the ground by blowing them away and for cleaning by
vacuuming dusts up and includes a blast fan (not shown) provided
within a casing 10, a driving unit 30 for rotationally driving the
blast fan, a blast duct 40 for discharging an air flow generated by
the rotating blast fan to the outside and a drive stop mechanism
(not shown) for setting driving states of the driving unit 30.
[0026] This blower 1 is provided with a grip 50 on the casing 10
and the driving unit 30 and the operator can carry around the
blower 1 by holding the grip 50. Then, the operator can sweep dusts
such as dead leaves and springs by blowing them away by discharging
the high-speed air flow from an air outlet of a blower pipe P1
coupled with the blast duct 40.
[0027] Still more, as shown in FIG. 5, the blower 1 of the
embodiment may be also provided with a cylindrical vacuum pipe P2
(suction pipe) at an air intake 11 formed in the casing 10 and with
a net-like dust collecting bag B at the blast duct 40 to vacuum up
and collect the dusts from a suction mouth of the vacuum pipe P2.
Thus, the blower 1 may be utilized also as a vacuum cleaner.
(Structure of Casing, Blast Fan and Blast Duct)
[0028] The casing 10 is a substantially circular box when seen from
the side as shown in FIG. 1 and is provided with a blast fan (not
shown) at the center part thereof.
[0029] The blast fan 20 shown in FIG. 3A and FIG. 3B has a
plurality of vanes 21 formed around a rotary shaft (not shown)
extending in the front-back direction in the center part of the
casing 10. The blower 1 is constructed so that the blast fan 20
generates the high-speed air flow in a direction from the outside
to the inside of the casing 10 when the blast fan 20 is rotating
around the rotary shaft.
[0030] Still more, as shown in FIG. 2, the blower 1 is provided
with the air intake 11 for taking ambient air into the casing 10 at
the left side face of the casing 10. The air intake 11 is circular
when seen from the front side and is formed at position approaching
the blast fan (not shown) (see FIG. 3A and FIG. 3B).
[0031] The blower 1 is also provided with a cylindrical blast duct
40 attached at the front part of the casing 10 to discharge the air
flow generated by the rotating blast fan to the outside of the
casing 10.
[0032] Then, the ambient air taken into the casing 10 through the
air intake 11 becomes the high-speed air flow by the rotating blast
fan as the blast fan is rotating. This air flow is discharged to
the outside through the blast duct 40.
(Structure of Driving Unit)
[0033] As shown in FIG. 1, the driving unit 30 is provided on the
right side portion of the casing 10 and has an engine (not shown)
stored within a box-like engine cover 31 attached on the right side
portion of the casing 10. An output shaft of the engine is linked
with the rotary shaft of the blast fan (not shown) so that the
engine of the driving unit 30 rotates the blast fan by its driving
force.
(Structure of Dust-proof Cover)
[0034] As shown in FIG. 1, the air intake 11 (see FIG. 2) of the
casing 10 is covered by a dust-proof cover 60 for preventing
extraneous materials from being sucked into the casing 10.
[0035] The dust-proof cover 60 has an outer peripheral plate 62
rising to the casing 10 side at an outer periphery of a side plate
61 that is seen circular from the side. A lattice-like opening 63
is formed through the side plate 61 and the peripheral plate
62.
[0036] A rear end portion of the peripheral plate 62 of the
dust-proof cover 60 is attached to a rear side portion of the air
intake 11 on the left side of the casing 10 by means of a hinge 64
as shown in FIG. 2. Thereby, the dust-proof cover 60 is capable of
turning about hinge 64 in the front-back direction and opening the
air intake 11.
[0037] The dust-proof cover 60 is also provided with an attachment
screw 65 at a front end part of the peripheral plate 62. As shown
in FIG. 3A, the attachment screw 65 is composed of a knob 65a
provided on an outer surface side of the dust-proof cover 60 and a
projection 65b inserted into a through hole 66 perforated through
the dust-proof cover 60. The projection 65b has a male thread
formed thereon. The projection 65b is also provided with a rubber
ring 65c fitted to retain it in the through hole 66.
[0038] When the dust-proof cover 60 is closed (see FIG. 1), the
projection 65b of the attachment screw 65 is inserted into an
attachment hole 12 (see FIG. 2) formed on the front side of the air
intake 11 of the casing 10. It is noted that a female thread is
formed on an inner peripheral surface of the attachment hole
12.
[0039] The projection 65b is screwed into the attachment hole 12
when the operator turns the whole attachment screw 65 around its
axis by holding a knob 65a of the attachment screw 65 in the state
in which the projection 65b of the attachment screw 65 is inserted
into the attachment hole 12. Thus, the front end part of the
dust-proof cover 60 may be fixed to the casing 10.
[0040] Then, when the blast fan (not shown) rotates in the state in
which the dust-proof cover 60 is closed as shown in FIG. 1, the
ambient air is taken into the dust-proof cover 60 through the
opening 63 and is suctioned into the casing 10 through the air
intake 11 (see FIG. 2). Thus, the rotating blast fan generates the
high-speed air flow.
[Structure of Drive Stop Mechanism]
[0041] The drive stop mechanism 70 shown in FIG. 3A and FIG. 3B is
a control mechanism that sets the engine 32 (see FIG. 4) of the
driving unit 30 in a drivable state when the dust-proof cover 60 is
closed over the air intake 11 and sets the engine 32 in a stop
state when the dust-proof cover 60 is opened from the air intake
11.
[0042] The drive stop mechanism 70 has a pressure sensor 71
provided within the casing 10, a depressing lever 72 that contacts
with a detecting part 71a of the pressure sensor 71 as shown in
FIG. 3A and a control section 73 (see FIG. 4) that sets the driving
state of the engine 32 of the driving unit 30 based on a detected
signal transmitted from the pressure sensor 71.
(Structure of Pressure Sensor)
[0043] The pressure sensor 71 shown in FIG. 3B may be any type of
conventionally known pressure sensors that detect pressure applied
to the detecting part 71a and outputs the detected signal
indicating variation of the pressure to the control section 73 (see
FIG. 4). However, its structure is not limited to that.
[0044] The pressure sensor 71 is installed within a hollow space 13
created on the front side of the air intake 11 in the casing 10.
The hollow space 13 has an opening and communicates with the air
intake 11, and also communicates with an opening on the inner side
of the attachment hole 12. The pressure sensor 71 is disposed near
an opening 13a on the side of the air intake 11 within the hollow
space 13.
(Structure of Depressing Lever)
[0045] The depressing lever 72 has a member substantially having a
shape of Z when seen planarly as shown in FIG. 3B and is disposed
within the hollow space 13 created in the casing 10. A cardinal end
portion 72a (one end) of the depressing lever 72 contacts with the
detecting part 71a of the pressure sensor 71 and a front end
portion 72b (other end) is inserted into the attachment hole 12 of
the casing 10.
[0046] Specifically, the cardinal end portion 72a of the depressing
lever 72 is disposed on the side of the air intake 11 within the
hollow space 13 and a front face of the cardinal end portion 72a
contacts with the detecting part 71a of the pressure sensor 71.
[0047] Still more, the cardinal end portion 72a has a through hole
72e formed further inward from the point at which the cardinal end
portion 72a is in contact with the pressure sensor 71. The
depressing lever 72 is attached to the casing 10 through an
anchoring shaft 72d inserted through the through hole 72e and
pivots about the anchoring shaft 72d.
[0048] Further, an intermediary portion 72c of the depressing lever
72 located outward from the cardinal end portion 72a is formed so
as to be inserted into the opening 13a on the air intake 11 side.
Accordingly, the intermediate portion 72c of the depressing lever
72 is exposed to the air intake 11 through the opening 13a.
[0049] The intermediate portion 72c of the depressing lever 72
extends from the cardinal end portion 72a toward the outside and
also extends forward from an outer end portion of the depressing
lever 72 to a position facing the inner-side opening of the
attachment hole 12.
[0050] The front end portion 72b of the depressing lever 72 formed
at the position facing the inner-side opening of the attachment
hole 12 extends toward the outside and is inserted into the
attachment hole 12.
[0051] The drive stop mechanism 70 is arranged to have the
projection 65b of the attachment screw 65 press the front end
portion 72b of the depressing lever 72 as shown in FIG. 3A.when the
projection 65b of the attachment screw 65 of the dust-proof cover
60 is inserted into the attachment hole 12 of the casing 10, i.e.,
when the dust-proof cover 60 is closed (see FIG. 1).
[0052] When the projection 65b of the attachment screw 65 thus
presses the front end portion 72b of the depressing lever 72, the
front end portion 72b of the depressing lever 72 is pushed inward.
Thereby, the whole depressing lever 72 turns inclined about the
anchoring shaft 72d in a direction of an arrow A in FIG. 3A.
[0053] When the whole depressing lever 72 turns inclined in the
direction of the arrow A, the cardinal end portion 72a of the
depressing lever 72 depresses the detecting part 71a of the
pressure sensor 71 and the pressure sensor 71 outputs the detected
signal to the control section 73 (see FIG. 4).
[0054] On the other hand, when the projection 65b of the attachment
screw 65 of the dust-proof cover 60 is not inserted into the
attachment hole 12, i.e., when the dust-proof cover 60 is opened
(see FIG. 2), no pressure is applied to the front end portion 72b
of the depressing lever 72 as shown in FIG. 3B. Accordingly the
depressing lever 72 does not turn inclined in this case and no
pressure is applied to the detecting part 71a of the pressure
sensor 71. As a result, the pressure sensor 71 outputs no detected
signal to the control section 73 (see FIG. 4).
[0055] Still more, when the vacuum pipe P2 is inserted into the air
intake 11 (see FIG. 5) with the dust-proof cover 60 opened as shown
in FIG. 6, an engaging projection P21 formed on the peripheral
surface of the vacuum pipe P2 is inserted into the opening 13a of
the hollow space 13 formed on the side of the air intake 11.
[0056] Thus the engaging projection P21 inserted into the opening
13a depresses the intermediate portion 72c of the depressing lever
72 and the intermediate portion 72c is pushed toward the front
side. Thereby, the whole depressing lever 72 turns inclined about
the anchoring shaft 72d in the direction of the arrow A.
[0057] Then, when the whole depressing lever 72 turns inclined in
the direction of the arrow A, the cardinal end portion 72a of the
depressing lever 72 depresses the detecting part 71a of the
pressure sensor 71 and the pressure sensor 71 outputs the detected
signal to the control section 73 (see FIG. 4).
(Structure of Control Section)
[0058] The control section 73 shown in FIG. 4 performs the drive
control of the engine 32 in response to the variation of the
pressure applied to the detecting part 71a of the pressure sensor
71. It is noted that the control section 73 is constructed by using
various known control circuits and its structure is
nonrestrictive.
[0059] The control section 73 sets up the engine 32 of the driving
unit 30 into the drivable state when the depressing lever 72
applies the pressure to the detecting part 71a of the pressure
sensor 71 and the pressure sensor 71 outputs the detected signal in
such cases when the dust-proof cover 60 is closed (see FIG. 3A) and
when the vacuum pipe P2 is inserted into the air intake 11. The
engine 32 may be driven to rotate the blast fan 20 in this
state.
[0060] The control section 73 also sets up the engine 32 in the
driving unit 30 into the stop state when the depressing lever 72
applies no pressure to the detecting part 71a of the pressure
sensor 71 and the pressure sensor 71 outputs no detected signal in
such a case when the dust-proof cover 60 is opened (see FIG. 3B).
The engine 32 is stopped and the blast fan 20 is stopped from
rotating in this state. Still more, because the engine 32 is kept
stopped, the blast fan 20 cannot rotate by any erroneous
operation.
[0061] The control section 73 is also arranged to set up the engine
32 of the driving unit 30 into the stop state when the pressure
being applied to the detecting part 71a of the pressure sensor 71
decreases.
[0062] Accordingly, the engine 32 is put into the stop state when
the attachment screw 65 shown in FIG. 3A is loosened and when the
pressure of the depressing lever 72 applied to the detecting part
71a of the pressure sensor 71 decreases. The engine 32 stops in
this state and the rotation of the blast fan 20 stops as well.
Still more, because the engine 32 is kept stopped, the blast fan 20
cannot rotate by any erroneous operation.
[Actions and Effects of Blower]
[0063] When the dust-proof cover 60 is opened and when the
projection 65b of the attachment screw 65 of the dust-proof cover
60 moves in a direction of being pulled out of the attachment hole
12 of the casing 10 as shown in FIG. 3A and FIG. 3B, the pressure
applied to the front end portion 72b of the depressing lever 72
from the projection 65b decreases in the blower 1 of the present
embodiment.
[0064] With the pressure applied to the front end portion 72b
decreasing, the pressure applied to the detecting part 71a of the
pressure sensor 71 from the cardinal end portion 72a of the
depressing lever 72 also decreases and the control section 73 sets
up the engine 32 (see FIG. 4) of the driving unit 30 into the stop
state.
[0065] Thus, the engine 32 is put into the stop state and the blast
fan 20 automatically stops from rotating when the dust-proof cover
60 is opened, so that it becomes possible to improve the safety of
the blower 1 when the air intake 11 is exposed to the outside in
attaching/detaching the vacuum pipe P2 to/from the air intake 11
(see FIG. 5) or when the dust-proof cover 60 is removed during
operation.
[0066] Still more, because the control section 73 (see FIG. 4) is
arranged to set up the engine 32 (see FIG. 4) of the driving unit
30 into the stop state when the pressure applied to the pressure
sensor 71 from the depressing lever 72 decreases, the engine 32
halts also when the projection 65b of the attachment screw 65 of
the dust-proof cover 60 is not completely pulled out, i.e., when
the attachment screw 65 of the dust-proof cover 60 is loosened.
[0067] Thus, the engine 32 is put into the stop state and the blast
fan 20 stops from rotating before the air intake 11 of the casing
10 is exposed to the outside, so that it is possible to improve the
safety of the blower 1 in opening the dust-proof cover 60 from the
air intake 11.
[0068] Still more, because the control section 73 (see FIG. 4)
changes the driving states of the engine 32 of the driving unit 30
in response to the variation of the pressure applied to the
pressure sensor 71 that varies depending on whether or not the
dust-proof cover 60 is attached, it is readily possible to change
over the driving states of the engine 32.
[0069] Furthermore, because the control section 73 (see FIG. 4)
changes the states of the engine 32 from the stop state to the
drivable state when the vacuum pipe P2 is attached to the air
intake 11 and the depressing lever 72 depresses the detecting part
71a of the pressure sensor 71, it is thus possible to change over
the driving states of the engine 32.
[Other Embodiment]
[0070] While the embodiment has been explained as an exemplary case
of the invention, the embodiment may be modified or changed
variously within a spirit and scope of the invention defined by the
appended claims.
[0071] For example, although the attachment screw 65 of the
dust-proof cover 60 is screwed into the attachment hole 12 of the
casing 10 as shown in FIG. 3B in the present embodiment, a
projection such as a pin and a hook formed on the dust-proof cover
60 may be fitted into an attachment hole formed in the casing 10 to
secure the dust-proof cover 60 to the casing 10 and to press the
depressing lever 72 by the projection.
[0072] Still more, although the present embodiment is arranged such
that the dust-proof cover 60 is attached to the casing 10 by the
hinge 64 so that the dust-proof cover 60 opens/closes as shown in
FIG. 2, it is also possible to arrange such that the whole
dust-proof cover may be removed out of the side of the casing
10.
* * * * *