U.S. patent application number 13/405992 was filed with the patent office on 2012-10-04 for power tool.
This patent application is currently assigned to MAKITA CORPORATION. Invention is credited to Hideharu MUTO, Shin NAKAMURA, Kenichi TABUSHI.
Application Number | 20120252328 13/405992 |
Document ID | / |
Family ID | 45808214 |
Filed Date | 2012-10-04 |
United States Patent
Application |
20120252328 |
Kind Code |
A1 |
MUTO; Hideharu ; et
al. |
October 4, 2012 |
POWER TOOL
Abstract
In a power tool in which a disc-shaped tool is attached to a
spindle that protrudes from a housing, a dust-collecting cover
provided on the housing for covering the disc-shaped tool has a
tool insertion opening. A rotation stopping tool that stops
rotation of the spindle can be inserted into the dust-collecting
cover through the tool inserting opening. The duct-collecting cover
is provided with a rubber ring that blocks the tool insertion
opening such that the opening can be opened and closed as
desired.
Inventors: |
MUTO; Hideharu; (Anjo-shi,
JP) ; NAKAMURA; Shin; (Anjo-shi, JP) ;
TABUSHI; Kenichi; (Anjo-shi, JP) |
Assignee: |
MAKITA CORPORATION
Anjo-shi
JP
|
Family ID: |
45808214 |
Appl. No.: |
13/405992 |
Filed: |
February 27, 2012 |
Current U.S.
Class: |
451/453 |
Current CPC
Class: |
B24B 23/022 20130101;
B24B 23/028 20130101; B24B 55/052 20130101 |
Class at
Publication: |
451/453 |
International
Class: |
B24B 55/10 20060101
B24B055/10; B24B 55/05 20060101 B24B055/05 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 31, 2011 |
JP |
2011-079521 |
Claims
1. A power tool comprising: a housing; a motor housed in the
housing; a spindle that protrudes from the housing; a disc-shaped
tool attached to the spindle; a dust-collecting cover that is
provided on the housing, and covers the disc-shaped tool; and a
tool insertion opening that is formed in the dust-collecting cover,
and enables a rotation stopping tool that stops rotation of the
spindle to be inserted into the dust-collecting cover, and an
opening and closing member provided on the dust-collecting cover
for opening and closing the tool insertion opening such that the
tool insertion opening can be opened and closed as desired.
2. The power tool according to claim 1, wherein the opening and
closing member is a ring-shaped rubber member that is mounted on
the dust-collecting cover and blocks the tool insertion
opening.
3. The power tool according to claim 2, wherein the dust-collecting
cover includes a main cover having an insert hole through which the
spindle can be inserted, a plate fixed to an upper surface of the
main cover and formed with an opening that communicates with the
insert hole, and a holder portion having an annular shape that is
concentric with the opening and formed integrally with an upper
surface of the plate so as to be coupled to the housing, wherein
the tool insertion opening is formed at around a base portion of
the holder portion in the vicinity of a boundary between the plate
and the holder portion.
4. The power tool according to claim 3, wherein a flange portion
that extends in radial directions is formed at a lower end portion
of the rubber member, and the rubber member is fitted on an outer
circumferential surface of the base portion so as to block the tool
insertion opening, while the flange portion is in close contact
with the upper surface of the plate.
Description
BACKGROUND OF INVENTION
[0001] This application claims the benefit of Japanese Patent
Application Number 2011-079521 filed on Mar. 31, 2011, the entirety
of which is incorporated by reference.
[0002] 1. Technical Field
[0003] The present invention relates to a power tool including a
dust-collecting cover that covers a disc-shaped tool attached to a
spindle, and collects dust produced when a workpiece is
machined.
[0004] 2. Background Art
[0005] A grinder disclosed in Japanese Patent Application
Publication No. 2011-56641 includes a spindle that is rotated by a
motor housed in a housing, a disc-shaped grinding tool attached to
the spindle, and a dust-collecting cover that covers the periphery
of the grinding tool. Generally, the grinder grinds a workpiece by
moving the rotating grinding tool on the workpiece while keeping
the grinding tool in contact with the workpiece. Dust produced
during grinding is collected in the dust-collecting cover, and then
discharged from a dust-collecting tube that communicates with the
interior of the dust-collecting cover, into a dust collector, via a
suction hose.
[0006] In a power tool as represented by the above-described
grinder, the dust-collecting cover has a tool insertion opening
through which a rotation stopping tool, such as a spanner, can be
inserted into the opening of the cover. When a lock mechanism for
stopping rotation of the spindle fails, rotation of the spindle can
be stopped by means of the rotation stopping tool inserted through
the opening formed on the cover. However, in the dust-collecting
cover having the tool insertion opening, the inside and outside of
the dust-collecting cover communicate with each other via the tool
insertion opening, and the air tightness within the dust-collecting
cover is reduced. Accordingly, efficiency of dust collection in the
dust-collecting cover is reduced.
[0007] On the other hand, if the tool insertion opening is closed
all the time so as to ensure air tightness, as the rotation
stopping tool cannot be inserted into the dust-collecting cover,
the spindle does not stop rotating when the lock mechanism for the
spindle fails.
SUMMARY OF THE INVENTION
[0008] This invention is proposed in view of the above situation,
and it is an object of the present invention to provide a power
tool in which dust is collected in a dust-collecting cover with
enhanced efficiency, and rotation of a spindle can be stopped using
a rotation stopping tool.
[0009] According to a first aspect of the present invention, there
is provided a power tool which includes a housing, a motor housed
in the housing, a spindle that protrudes from the housing, a
disc-shaped tool attached to the spindle, a dust-collecting cover
that is provided on the housing, and covers the disc-shaped tool,
and a tool insertion opening that is formed in the dust-collecting
cover, and enables a rotation stopping tool that stops rotation of
the spindle to be inserted into the dust-collecting cover. In the
power tool, the dust-collecting cover is provided with an opening
and closing member that blocks the tool insertion opening such that
the tool insertion opening can be opened and closed as desired.
[0010] In the power tool according to a second aspect of the
present invention, in the first aspect of the present invention,
the opening and closing member may be a ring-shaped rubber member
that is mounted on the dust-collecting cover and blocks the tool
insertion opening.
[0011] In the power tool according to the first aspect of the
present invention, the opening and closing member blocks the tool
insertion opening formed in the dust-collecting cover, and
therefore, the air tightness of the dust-collecting cover is
improved. Accordingly, the efficiency of dust collection in the
dust-collecting cover can be enhanced. If the tool insertion
opening is rendered open to the dust-collecting cover, using the
opening and closing member, the rotation stopping tool can be
inserted into the dust-collecting cover, through the opened tool
insertion opening, so as to stop rotation of the spindle.
[0012] When the tool insertion opening is blocked by the
ring-shaped rubber member, the air tightness of the dust-collecting
cover is improved, and the efficiency of dust collection in the
dust-collecting cover can be enhanced. Further, when the rubber
member is rolled up, the tool insertion opening of the
dust-collecting cover appears, and the rotation stopping tool can
be inserted into the dust-collecting cover through the tool
insertion opening, so as to stop rotation of the spindle.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is a side cross-sectional view of a disc grinder as
one embodiment of the present invention.
[0014] FIG. 2 is a plan view of a dust-collecting cover included in
the disc grinder.
[0015] FIG. 3 is a view explaining the time when rotation of a
spindle of the disc grinder is stopped.
DETAILED DESCRIPTION OF THE EMBODIMENT
[0016] One embodiment of the present invention will be described
with reference to FIG. 1 through FIG. 3. A disc grinder 1 shown in
FIG. 1 includes a housing 10 and a dust-collecting cover 20. The
housing 10 consists of a motor housing 11 and a gear housing 15,
The disc grinder 1 is one example of power tool of the present
invention.
[0017] The motor housing 11 is formed in a cylindrical shape, and a
motor M is housed in the motor housing 11. A rotary shaft 12 of the
motor M is rotatably supported in the motor housing 11 via a
bearing 13, and a first bevel gear 14 is provided at a distal end
of the rotary shaft 12.
[0018] The gear housing 15 is mounted to the front (the left-hand
side in FIG. 1) of the motor housing 11, and the rotary shaft 12
supported in the motor housing 11 protrudes into the gear housing
15. In addition, a spindle 16 is rotatably supported in the gear
housing 15 via bearings 17, 18, to extend in a direction
perpendicular to the rotary shaft 12. A second bevel gear 19 is
mounted on an upper portion of the spindle 16. With the first bevel
gear 14 engaging with the second bevel gear 19, rotation of the
rotary shaft 12 is transmitted to the spindle 16. The lower end of
the spindle 16 protrudes downwardly of the gear housing 15, and an
external threaded portion 16A is formed on an outer circumferential
surface of a lower end portion of the spindle 16, In the disc
grinder 1, a disc-shaped grinding tool (not shown) is sandwiched
between an inner flange and a lock nut screwed on the external
threaded portion 16A, and is thus attached to the spindle 16. The
disc-shaped grinding tool is one example of disc-shaped tool of the
present invention.
[0019] As shown in FIG. 1 and FIG. 2, the dust-collecting cover 20
includes a main cover 21, an auxiliary cover 22, a plate 23, a
holder portion 24, and a rubber ring 26. The main cover 21 and the
auxiliary cover 23 are formed of resin, and the main cover 21 is
provided at its upper surface with an insert hole 21A through which
the spindle 16 can be inserted. The auxiliary cover 22 is
detachably or removably attached to the main cover 21. In a
condition where the auxiliary cover 22 is attached to the main
cover 21, the dust-collecting cover 20 assumes a generally
bowl-like shape that has a larger diameter than the disc-shaped
grinding tool and is open downwards, and surrounds the periphery of
the grinding tool. A dust-collecting tube 21B that communicates
with the interior of the main cover 21 is provided on the outer
surface of the main cover 21. A dust collector can be connected to
the dust-collecting tube 21B via a suction hose.
[0020] The plate 23 is made of metal, and is fixed to the upper
surface of the main cover 21 by means of four screws 23A. The plate
23 is formed with an opening 23B that communicates with the insert
hole 21A of the main cover 21. The holder portion 24, which is made
of metal and has an annular shape that is concentric with the
opening 23B, is formed integrally with the upper surface of the
plate 23. By fitting the holder portion 24 on a lower end portion
of the gear housing 15 and fastening it with a screw 24A, the
duct-collecting cover 20 is coupled to the gear housing 15.
[0021] As shown in FIG. 1 and FIG. 3, a tool insertion slot 24B is
formed in a base portion of the holder portion 24 in the vicinity
of the boundary between the plate 23 and the holder portion 24. The
tool insertion slot 24B is used for inserting a spanner 25 into the
dust-collecting cover 20. Further, the rubber ring 26, which has a
flange portion 26A (see FIG. 3) provided at its lower end portion
and extending in radial directions, is fitted along the outer
circumferential surface of the above-mentioned base portion. As
shown in FIG. 1, the rubber ring 26, which is in close contact with
the outer circumferential surface of the base portion, normally
blocks the tool insertion slot 24B, and the flange portion 26A,
which is in close contact with the upper surface of the plate 23,
closes a clearance between the rubber ring 26 and the upper
surface. The rubber ring 26 is one example of ring-shaped rubber
member of the present invention.
[0022] Next, the operation of the disc grinder 1 will be described.
When grinding a workpiece with the disc grinder 1, the operator
holds the motor housing 11, and turns a switch ON so as to drive
the motor M to operate the dust collector. The grinding tool that
rotates with the motor M thus driven is moved on a worked surface
of the workpiece while being kept in contact with the worked
surface, so as to grind the worked surface. Dust produced during
grinding of the worked surface is sucked and collected from the
duct-collecting tube 21B into the dust collector via the suction
hose. At this time, the rubber ring 26 blocks the tool insertion
slot 24B, and the flange portion 26A closes the clearance between
the rubber ring 26 and the upper surface of the plate 23;
therefore, the inside and outside of the dust-collecting cover 20
do not communicate with each other, and the dust-collecting cover
20 is sealed with improved tightness. Accordingly, the dust is
prevented from scattering out of the dust-collecting cover 20, and
the dust-collecting efficiency of the dust-collecting cover 20 is
enhanced.
[0023] In the meantime, if a lock mechanism for stopping rotation
of the spindle 16 fails when a worn grinding tool is to be replaced
by a new one, for example, the rotation of the spindle 16 needs to
be stopped by a spanner 25. In this case, the rubber ring 26 is
rolled up so that the tool insertion slot 24B is open to a surface
of the dust-collecting cover 20, as shown in FIG. 3. Then, as shown
in FIG. 3, the spanner 25 is inserted into the dust-collecting
cover 20 through the tool insertion slot 24B, to be engaged with a
chamfered portion formed on the spindle 16, so as to stop rotation
of the spindle 16. The spanner 25 is one example of rotation
stopping tool of the present invention.
EFFECT BY THE EMBODIMENT
[0024] In the disc grinder 1 of this embodiment, the rubber ring 26
blocks the tool insertion slot 24B, so that the dust-collecting
cover 20 is sealed with improved tightness. As a result, the
efficiency with of dust collection in the dust-collecting cover 20
can be enhanced. Also, by rolling up the rubber ring 26, it is
possible to open the tool insertion slot 24B to the dust-collecting
cover 20. Then it becomes possible to insert the spanner 25 into
the dust-collecting cover 20 through the tool insertion slot 24B,
and stop rotation of the spindle 16 with the spanner 25.
[0025] The present invention is not limited to the above-described
embodiment, but may be embodied by changing a part of the
construction as needed, without departing from the principle of the
invention. For example, the rubber ring 26 may be replaced by an O
ring made of rubber, and the O ring may be fitted along the outer
circumferential surface of the above-mentioned base portion, so
that the O ring blocks the tool insertion slot 24B.
[0026] Unlike the above-described embodiment, an opening and
closing plate that is rotatable in the vertical direction via a
hinge member, for example, may be mounted on the holder portion 24,
and the tool insertion slot 24B may be blocked by the opening and
closing plate, such that the tool insertion slot 24B can be opened
or closed as desired. With this arrangement, dust can be collected
in the dust-collecting cover 20 with enhanced efficiency, and the
rotation of the spindle 16 can be stopped by the spanner 25, as in
the above-described embodiment.
[0027] As a further example, a rubber magnet that is detachably
attached to the holder portion 24 may be provided, in place of the
above-described rubber ring 26, for blocking the tool insertion
slot 24B such that the tool insertion slot 24B can be opened or
closed as desired. In this case, too, dust can be collected in the
dust-collecting cover 20 with enhanced efficiency, and the rotation
of the spindle 16 can be stopped by the spanner 25, as in the
above-described embodiment. The opening and closing plate and the
rubber magnet are examples of opening and closing member of the
present invention. While the present invention is applied to the
disc grinder in the above-described embodiment, the application is
not limited to this example, but the present invention may also be
applied to a power tool, such as a sander or a cutter having a
dust-collecting cover.
[0028] It is explicitly stated that all features disclosed in the
description and/or the claims are intended to be disclosed
separately and independently from each other for the purpose of
original disclosure as well as for the purpose of restricting the
claimed invention independent of the composition of the features in
the embodiments and/or the claims. It is explicitly stated that all
value ranges or indications of groups of entities disclose every
possible intermediate value or intermediate entity for the purpose
of original disclosure as well as for the purpose of restricting
the claimed invention, in particular as limits of value ranges.
* * * * *