U.S. patent application number 16/065490 was filed with the patent office on 2018-12-27 for grinding device and grinding implement for said grinding device.
This patent application is currently assigned to NEW REGISTON CO., LTD.. The applicant listed for this patent is NEW REGISTON CO., LTD.. Invention is credited to Tatsuo Kitatani, Daisuke Takita, Kenji Yamauchi.
Application Number | 20180369982 16/065490 |
Document ID | / |
Family ID | 59090004 |
Filed Date | 2018-12-27 |
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United States Patent
Application |
20180369982 |
Kind Code |
A1 |
Yamauchi; Kenji ; et
al. |
December 27, 2018 |
GRINDING DEVICE AND GRINDING IMPLEMENT FOR SAID GRINDING DEVICE
Abstract
A grinding device has a support unit attached to a rotary shaft
so as to be rotatable integrally with the rotary shaft, and a
grinding element stacked on the support unit and having an uneven
grinding surface formed by a plurality of abrasive grains. The
support unit has, in a surface thereof, protruding surface portions
to be brought into contact with a rear surface of the grinding
element when in use, and recessed surface portions recessed from
the protruding surface portions, alternately located in a
circumferential direction. An engagement mechanism which makes an
engagement at each of predetermined angular positions so as to
retain the grinding element or the support unit moved by a
predetermined angle in the circumferential direction, is provided
between the support unit and the grinding element, between the
rotary shaft and the grinding element, or between the rotary shaft
and the support unit.
Inventors: |
Yamauchi; Kenji;
(Kaizuka-shi, Osaka, JP) ; Kitatani; Tatsuo;
(Kaizuka-shi, Osaka, JP) ; Takita; Daisuke;
(Kaizuka-shi, Osaka, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
NEW REGISTON CO., LTD. |
Kaizuka-shi, Osaka |
|
JP |
|
|
Assignee: |
NEW REGISTON CO., LTD.
Kaizuka-shi, Osaka
JP
|
Family ID: |
59090004 |
Appl. No.: |
16/065490 |
Filed: |
September 2, 2016 |
PCT Filed: |
September 2, 2016 |
PCT NO: |
PCT/JP2016/075869 |
371 Date: |
June 22, 2018 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B24B 23/02 20130101;
B24D 7/16 20130101; B24D 9/08 20130101; B24B 45/00 20130101 |
International
Class: |
B24B 23/02 20060101
B24B023/02; B24D 9/08 20060101 B24D009/08 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 25, 2015 |
JP |
2015-253715 |
Claims
1. A grinding device comprising: a support unit attached to a
rotary shaft driven by a rotary drive unit, so as to be rotatable
integrally with the rotary shaft; and a grinding element stacked on
the support unit and having an uneven grinding surface formed by a
plurality of abrasive grains, wherein the support unit has, in a
surface thereof, protruding surface portions to be brought into
contact with a rear surface of the grinding element when in use,
and recessed surface portions recessed from the protruding surface
portions, the protruding surface portions and recessed surface
portions being alternately located in a circumferential direction,
and the grinding device also comprises an engagement mechanism
which makes an engagement at each of predetermined angular
positions so as to retain the grinding element or the support unit
moved by a predetermined angle in the circumferential direction,
the engagement mechanism being located between the support unit and
the grinding element, between the rotary shaft and the grinding
element, or between the rotary shaft and the support unit.
2. The grinding device according to claim 1, wherein the engagement
mechanism includes at least one engaging projection provided on one
of the support unit and the grinding element, and a plurality of
engaging holes provided in the other of the support unit and the
grinding element at respective predetermined angular positions so
as to be engageable with or disengageable from the engaging
projections.
3. The grinding device according to claim 1, wherein the engagement
mechanism includes a ratchet gear constituting an internal gear
attached to an inner circumferential surface of the grinding
element or the support unit and having a predetermined pitch along
the circumferential direction, and at least one ratchet pawl
attached to the rotary shaft so as to be engaged with the ratchet
gear.
4. The grinding device according to claim 1, further comprising a
displacement mechanism which moves the grinding element or the
support unit by a predetermined angle in the circumferential
direction in response to engaging action of the engagement
mechanism.
5. The grinding device according to claim 4, wherein the
displacement mechanism includes a guide member provided on one of
the grinding element and the support unit, and a displacement
member attached to an outer circumference of the guide member so as
to be movable in an axial direction along the guide member but be
restricted from moving in the circumferential direction, and the
engagement mechanism includes at least one engaging pin provided on
an outer circumferential surface of the displacement member so as
to project outward in a radial direction, and an engaging groove
formed on an entirety of the inner circumferential surface of the
other of the grinding element and the support unit and including
stepped portions each formed at a predetermined angular
position.
6. The grinding device according to claim 4, wherein the engagement
mechanism includes a first face gear attached to one of the support
unit and the grinding element and having a predetermined pitch
along the circumferential direction, and a second face gear
attached to the other of the support unit and the grinding element
and having a pitch which allows the second face gear to mesh with
the first face gear, along the circumferential direction, the
displacement mechanism includes a third face gear attached to an
outer circumference of the second face gear so as to be movable in
the axial direction but be restricted from moving in the
circumferential direction, and having a pitch which allows the
third face gear to mesh with the first face gear, along the
circumferential direction, and the third face gear has teeth
deviated from the second face gear in the circumferential
direction.
7. A grinding implement to be attached, for use, to a base member
which is attached to a rotary shaft driven by a rotary drive unit,
so as to be rotatable integrally with the rotary shaft and which
has an engaging projection on a surface thereof, the grinding
implement comprising: a protrusion/recess-forming member attached
to the base member and configured to form protruding surface
portions and recessed surface portions recessed from the protruding
surface portions, alternately located in a circumferential
direction; and a grinding element stacked on the
protrusion/recess-forming member and having an uneven grinding
surface formed by a plurality of abrasive grains, wherein the
protrusion/recess-forming member has an attachment hole to be
engaged with the engaging projection so as to attach the
protrusion/recess-forming member on the base member, and the
grinding element has a plurality of engaging holes each provided at
a predetermined angular position so as to be engageable with or
disengageable from the engaging projection.
8. A grinding implement to be attached, for use, to a support unit
which is attached to a rotary shaft driven by a rotary drive unit,
so as to be rotatable integrally with the rotary shaft, and which
has in a surface thereof protruding surface portions and recessed
surface portions recessed from the protruding surface portions, the
protruding surface portions and recessed surface portions being
alternately located in a circumferential direction, the grinding
implement comprising: a grinding element stacked on the support
unit and having an uneven grinding surface formed by a plurality of
abrasive grains; and a guide member attached to a rear surface of
the grinding element, wherein the grinding element is attached to
the support unit by inserting the guide member into an inner
circumference of a displacement member provided on the support
unit, so as to move by a predetermined angle in the circumferential
direction with respect to the support unit in response to engaging
action of a displacement mechanism included in the support unit.
Description
TECHNICAL FIELD
[0001] The present invention relates to a grinding device for
grinding an object, and a grinding implement for use with the
grinding device.
BACKGROUND ART
[0002] Grinding devices, such as a disk grinder having a grinding
element made of grindstone or a coated abrasive product, are widely
utilized to grind or polish a work formed of common steel,
stainless steel, aluminum, plastic, or the like (see, for example,
Patent Literature 1). Such a grinding device 100 is generally
configured as shown in FIG. 26. More specifically, a grinding
element 130 having an uneven grinding surface 131 formed by a
plurality of abrasive grains is fixed on a flat plate-shaped
support member 120, and the support member 120 and the grinding
element 130 are integrally supported by a rotary shaft. When the
rotary shaft is driven by a rotary drive unit 111, the support
member 120 and the grinding element 130 are made to rotate by the
rotary shaft, so that the recesses and the projections of the
grinding surface 131 of the grinding element 130 grind or polish a
work.
CITATION LIST
Patent Literature
[0003] PTL 1: Japanese Unexamined Patent Application Publication
No. 2015-42424
SUMMARY OF INVENTION
Technical Problem
[0004] However, with the foregoing conventional grinding device
100, the grinding or polishing load is normally imposed over the
same region, and therefore the abrasive grains 132 in that region
(see FIG. 27) are evenly worn. To be more specific, whereas the
surface 131 of the grinding element 130 is uneven because of the
presence of the abrasive grains 132, in the new and unused state
shown in FIG. 27(a), the abrasive grains 132 are evenly worn out as
shown in FIG. 27(b), as result of a grinding or polishing a work W
with the grinding element 130, and the surface 131 of the grinding
element 130 becomes smooth. Under such a condition called
"dulling", the blades of the abrasive grains 132 become blunt and
the cutting performance is drastically degraded, irrespective of
whether the abrasive grains 132 still exist. The mentioned
phenomenon leads to an increase in grinding resistance and grinding
heat, which often provokes a grinding burn.
[0005] The present invention has been made in order to solve the
above problem, and provides a grinding device that prevents the
surface of a grinding element from being evenly worn, thereby
preventing a drastic decline in grinding capability and a grinding
burn, and a grinding implement for the grinding device.
Solution to Problem
[0006] A grinding device according to the present invention which
solves the above problem includes a support unit attached to a
rotary shaft driven by a rotary drive unit, so as to be rotatable
integrally with the rotary shaft, and a grinding element stacked on
the support unit and having an uneven grinding surface formed by a
plurality of abrasive grains. The support unit has, in a surface
thereof, protruding surface portions to be brought into contact
with a rear surface of the grinding element when in use, and
recessed surface portions recessed from the protruding surface
portions, the protruding surface portions and recessed surface
portions being alternately located in a circumferential direction.
An engagement mechanism which makes an engagement at each of
predetermined angular positions so as to retain the grinding
element or the support unit moved by a predetermined angle in the
circumferential direction, is provided between the support unit and
the grinding element, between the rotary shaft and the grinding
element, or between the rotary shaft and the support unit.
[0007] In the grinding device according to the present invention,
the support unit has in the surface thereof the protruding surface
portions and the recessed surface portions, alternately located in
the circumferential direction, out of which only the protruding
surface portions are in contact with the grinding element.
Accordingly, when the grinding element grinds a work, the pressure
of the grinding element against the work concentrates only in the
region where the protruding surface portions are in contact with
the grinding element, and therefore the grinding element grinds the
work in the region where the protruding surface portions are in
contact with the grinding element, but in the region where the
grinding element opposes the recessed surface portions, the
grinding element is in contact with the work but merely slides on
the surface of the work without actually grinding the work.
Therefore, in the region where the protruding surface portions are
in contact with the grinding element, the abrasive grains are
evenly worn, so that the grinding surface, which is initially
uneven, is smoothed. However, the relative position of the grinding
element with respect to the support unit, i.e., the protruding
surface portions, can be changed. Accordingly, the uneven region of
the grinding surface, which contributes to grinding the work, can
be brought into contact with the protruding surface portions, by
changing the position of the grinding element in contact with the
protruding surface portions, so that the grinding capability of the
grinding element can be recovered. In this process, changing the
relative position between the grinding element and the support
unit, that is, the protruding surface portions, at each of the
predetermined angular positions can ensure that the uneven region
of the grinding surface is brought into contact with the protruding
surface portions. Changing the position of the grinding element
with respect to the protruding surface portions when the grinding
capability begins to decline suppresses a drastic decline in
grinding capability, thereby preventing an increase in friction due
to the decline in grinding capability, thus preventing a grinding
burn.
[0008] Here, the term "grind" includes not only scraping off a
surface as generally construed, but also a concept of "polish"
having a meaning of polishing a surface, and thus broadly refers to
cutting away the surface of a work to make the surface smooth.
[0009] In the grinding device according to a preferred embodiment,
the engagement mechanism may include at least one engaging
projection provided on one of the support unit and the grinding
element, and a plurality of engaging holes provided in the other of
the support unit and the grinding element at respective
predetermined angular positions so as to be engageable with or
disengageable from the engaging projections.
[0010] In the grinding device according to another preferred
embodiment, the engagement mechanism may include a ratchet gear
constituting an internal gear attached to an inner circumferential
surface of the grinding element or the support unit and having a
predetermined pitch along the circumferential direction, and at
least one ratchet pawl attached to the rotary shaft so as to be
engaged with the ratchet gear.
[0011] The grinding device according to still another preferred
embodiment may further include a displacement mechanism which moves
the grinding element or the support unit by a predetermined angle
in the circumferential direction in response to engaging action of
the engagement mechanism.
[0012] The provision of the displacement mechanism as described
above allows the grinding element to be automatically moved
relative to the support unit, without the need for the user of the
grinding device to intentionally move the grinding element relative
to the support unit. Therefore, the user can continue to use the
grinding device for a long time, without worrying about a decline
in grinding capability.
[0013] In the grinding device according to a more preferred
embodiment, the displacement mechanism may include a guide member
provided on one of the grinding element and the support unit, and a
displacement member attached to an outer circumference of the guide
member so as to be movable in an axial direction along the guide
member but be restricted from moving in the circumferential
direction. The engagement mechanism may include at least one
engaging pin provided on an outer circumferential surface of the
displacement member so as to project outward in the radial
direction, and an engaging groove formed on an entirety of the
inner circumferential surface of the other of the grinding element
and the support unit, and including stepped portions each formed at
a predetermined angular position.
[0014] In the grinding device according to another more preferred
embodiment, the engagement mechanism may include a first face gear
attached to one of the support unit and the grinding element and
having a predetermined pitch along the circumferential direction,
and a second face gear attached to the other of the support unit
and the grinding element and having a pitch which allows the second
face gear to mesh with the first face gear, along the
circumferential direction. The displacement mechanism may include a
third face gear attached to an outer circumference of the second
face gear so as to be movable in the axial direction but be
restricted from moving in the circumferential direction, and having
a pitch which allows the third face gear to mesh with the first
face gear, along the circumferential direction, and the third face
gear has teeth deviated from the second face gear in the
circumferential direction.
[0015] A grinding implement according to the present invention is a
grinding implement to be attached, for use, to a base member which
is attached to a rotary shaft driven by a rotary drive unit, so as
to be rotatable integrally with the rotary shaft and which has an
engaging projection on a surface thereof. The grinding implement
includes a protrusion/recess-forming member attached to the base
member and configured to form protruding surface portions and
recessed surface portions recessed from the protruding surface
portions, alternately located in a circumferential direction, and a
grinding element stacked on the protrusion/recess-forming member
and having an uneven grinding surface formed by a plurality of
abrasive grains. The protrusion/recess-forming member has an
attachment hole to be engaged with the engaging projection so as to
attach the protrusion/recess-forming member on the base member, and
the grinding element has a plurality of engaging holes each
provided at a predetermined angular position so as to be engageable
with or disengageable from the engaging projection.
[0016] Another grinding implement according to the present
invention is a grinding implement to be attached, for use, to a
support unit which is attached to a rotary shaft driven by a rotary
drive unit, so as to be rotatable integrally with the rotary shaft,
and which has in a surface thereof protruding surface portions and
recessed surface portions recessed from the protruding surface
portions, the protruding surface portions and recessed surface
portions being alternately located in a circumferential direction.
The grinding implement includes a grinding element stacked on the
support unit and having an uneven grinding surface formed by a
plurality of abrasive grains, and a guide member attached to a rear
surface of the grinding element. The grinding element is attached
to the support unit by inserting the guide member into an inner
circumference of a displacement member provided on the support
unit, so as to move by a predetermined angle in the circumferential
direction with respect to the support unit in response to engaging
action of a displacement mechanism included in the support
unit.
Advantageous Effects of Invention
[0017] The grinding device and the grinding implement therefor
according to the present invention prevent the surface of the
grinding element from being evenly worn, thereby preventing a
drastic decline in grinding capability and a grinding burn.
BRIEF DESCRIPTION OF DRAWINGS
[0018] FIG. 1 is a perspective view showing a grinding device
according to a first embodiment of the present invention.
[0019] FIG. 2 is an exploded perspective view of the grinding
device shown in FIG. 1.
[0020] FIG. 3 is a plan view of a grinding element of the grinding
device shown in FIG. 1.
[0021] FIG. 4(a) and FIG. 4(b) are front views of the grinding
element and a support unit of the grinding device shown in FIG. 1,
respectively showing a first and a second positional relationship
between protruding surface portions and the grinding element.
[0022] FIG. 5 is an exploded perspective view showing a first
modification of the grinding device according to the first
embodiment of the present invention.
[0023] FIG. 6 is a plan view showing a modification of the support
unit of the grinding device shown in FIG. 1 and FIG. 5.
[0024] FIG. 7 is an exploded perspective view showing a second
modification of the grinding device according to the first
embodiment of the present invention.
[0025] FIG. 8 is a plan view showing a modification of the support
unit of the grinding device shown in FIG. 7.
[0026] FIG. 9 is a plan view showing another modification of the
support unit of the grinding device shown in FIG. 7.
[0027] FIG. 10 is a perspective view showing a third modification
of the grinding device according to the first embodiment of the
present invention.
[0028] FIG. 11 is an exploded perspective view showing a grinding
device according to a second embodiment of the present
invention.
[0029] FIG. 12 is a perspective view showing an assembled state of
the grinding device shown in FIG. 11.
[0030] FIG. 13 is a cross-sectional view taken along a line A-A in
FIG. 12.
[0031] FIG. 14 is an exploded perspective view showing a grinding
device according to a third embodiment of the present
invention.
[0032] FIG. 15 is an exploded perspective view of the grinding
device shown in FIG. 14, as viewed from the rotary drive unit
side.
[0033] FIG. 16 is a vertical cross-sectional view of the grinding
device shown in FIG. 14.
[0034] FIG. 17 is a perspective view showing a support unit of the
grinding device shown in FIG. 14.
[0035] FIG. 18 is a vertical cross-sectional view of the support
unit shown in FIG. 17, from which an inner cylindrical portion is
omitted.
[0036] FIG. 19 is an exploded perspective view showing a grinding
device according to a fourth embodiment of the present
invention.
[0037] FIG. 20 is an exploded perspective view of the grinding
device shown in FIG. 19, as viewed from the rotary drive unit
side.
[0038] FIG. 21 is a vertical cross-sectional view of the grinding
device shown in FIG. 19.
[0039] FIG. 22 shows schematic drawings for explaining operation of
a first face gear to a third face gear of the grinding device shown
in FIG. 19.
[0040] FIG. 23 shows schematic drawings for explaining operation of
the first face gear to the third face gear of the grinding device
shown in FIG. 19.
[0041] FIG. 24 is a front view showing a modification of protruding
surface portions and recessed surface portions of the grinding
device according to the present invention.
[0042] FIG. 25 is a front view showing another modification of the
protruding surface portions and the recessed surface portions of
the grinding device according to the present invention.
[0043] FIG. 26 is a perspective view showing a conventional
grinding device.
[0044] FIG. 27(a) and FIG. 27(b) are partially enlarged schematic
front views showing an area at and around the grinding element of
the grinding device shown in FIG. 26; FIG. 27(a) shows an unused
state of the grinding element, and FIG. 27(b) shows a used state
thereof.
DESCRIPTION OF EMBODIMENTS
[0045] Hereafter, embodiments of the present invention will be
described with reference to the accompanying drawings. Grinding
devices 1 according to the embodiments are each a device for
grinding a work W (see FIG. 4) formed of common steel, stainless
steel, aluminum, plastic, or the like. Although the following will
describe a free-hand grinder such as a disk grinder, to be operated
by a user with the hands, the present invention is also applicable
to a grinding machine that can automatically grind the work W when
the work W is set thereon. In the following description, an axial
direction, a circumferential direction, and a radial direction are
defined on the basis of a rotary shaft 12 of the grinding device 1.
In addition, the face of the grinding device 1 which makes contact
with the work W is defined as a front surface, and the opposite
face as a rear surface.
[0046] With reference to FIG. 1 to FIG. 3, the grinding device 1
according to a first embodiment of the present invention will be
described. As shown in FIG. 1 and FIG. 2, the grinding device 1
includes: a support unit 20 which is attached to the rotary shaft
12 driven by a rotary drive unit 11, so as to be rotatable
integrally with the rotary shaft 12; a grinding element 30 which is
stacked on the support unit 20; and a fixing unit 40 which fixes
the grinding element 30 to the support unit 20. The rotary drive
unit 11 includes a built-in rotary driving source such as a motor
which rotates with power supplied through a power cord 15, so that
when the rotary driving source is activated the rotary shaft 12 is
made to rotate. Here, a hydraulic motor or a pneumatic motor which
utilizes compressed air may be used as the rotary driving source,
and, for example, the rotary drive unit 11 may be composed of an
air tool with a built-in pneumatic motor. Any one of the known
rotary drive units 11 may be employed, provided that the drive unit
is capable of driving the rotary shaft 12.
[0047] The support unit 20 includes two members, namely, a
protrusion/recess-forming member 23 and a base member 24 having the
protrusion/recess-forming member 23 fixed to the surface thereof.
In the surface of the support unit 20, protruding surface portions
21 which make contact with the rear surface of the grinding element
30 when in use, and recessed surface portions 22 recessed from the
protruding surface portions 21, are alternately formed in the
circumferential direction, because of the presence of the
protrusion/recess-forming member 23.
[0048] The base member 24 is formed in a disk shape having the same
diameter as the grinding element 30, and has a through hole 24a
formed at the center thereof for inserting the rotary shaft 12
therethrough. Two engaging projections 51 stick out parallel to the
axial direction of the rotary shaft 12, from the surface of the
base member 24 at positions around the through hole 24a. Here, the
term "disk shape" includes not only a flat plate having no recess,
but also such a shape in which, in a side view, the peripheral
portion of the plate is flat while the central portion is recessed
in a cup shape.
[0049] The protrusion/recess-forming member 23 includes a central
portion 25 having a diameter smaller than the outer diameter of the
base member 24, and a plurality of peripheral portions 26 radially
extending from the central portion 25, and the central portion 25
and the peripheral portions 26 are integrally formed. The
peripheral portions 26 each extend to a position corresponding to
the outer edge of the base member 24. The central portion 25 has a
through hole 25a formed for inserting the rotary shaft 12
therethrough. In addition, attachment holes 26a for inserting the
engaging projections 51 therethrough to attach the
protrusion/recess-forming member 23 to the base member 24 are
formed in the peripheral portion 26 at locations where the engaging
projections 51 are located when the protrusion/recess-forming
member 23 is attached to the base member 24. The attachment holes
26a each have a size with a clearance which allows the engaging
projection 51 to penetrate therethrough. In the
protrusion/recess-forming member 23, the peripheral portions 26
form the protruding surface portions 21 and the portions between
the protruding surface portions 21 adjacent to each other form the
recessed surface portions 22, whereby the protruding surface
portions 21 and the recessed surface portions 22 are integrally
provided, and the protruding surface portions 21 and the recessed
surface portion 22 recessed from the protruding surface portion 21
are alternately located in the circumferential direction. Since the
peripheral portions 26 extend radially, the
protrusion/recess-forming member 23 is formed such that the
protruding surface portions 21 and the recessed surface portions 22
also form a radial pattern.
[0050] The protrusion/recess-forming member 23 and the base member
24 are formed of, for example, a desired material such as a metal,
a resin, and rubber. As the material for forming the
protrusion/recess-forming member 23 and the base member 24, a
material most suitable for the materials of the grinding element 30
and the work W may be selected as appropriate. The
protrusion/recess-forming member 23 and the base member 24 do not
necessarily need to be formed of the same material. Employing
different materials for the protrusion/recess-forming member 23 and
the base member 24 allows various types of grinding elements 30 and
works W to be adopted or handled, thereby improving the versatility
of the grinding device 1. Further, when different materials are to
be adopted for the protrusion/recess-forming member 23 and the base
member 24, the material for the protrusion/recess-forming member 23
and the material for the base member 24 can be individually
selected, and therefore the support unit can have flexibility
depending on a combination of the protrusion/recess-forming member
23 and the base member 24.
[0051] The grinding element 30 has a disk shape, with an uneven
grinding surface 31 formed by a plurality of abrasive grains. As
the grinding element 30, for example, a known grindstone, a coated
abrasive product such as a multiple disk and a sanding disk, or a
flexible grinding material such as a non-woven abrasive fabric may
be used. Here, the term "disk shape" includes not only to a flat
plate having no recess, but also such a shape in which, in a side
view, the peripheral portion of the plate is flat while the central
portion is recessed in a cup shape.
[0052] The grinding element 30 has: a through hole 30a formed at
the center thereof for inserting the rotary shaft 12 therethrough;
and two engaging holes 52 formed around the through hole 30a at
positions where the respective engaging projections 51 are located
when the grinding element 30 is stacked on the support unit 20.
Each engaging hole 52 extends in the circumferential direction, so
that the engaging projection 51 is movable therein within the range
corresponding to the length of the engaging hole 52. Accordingly,
the grinding element 30 is configured to be displaceable in the
circumferential direction about the rotary shaft 12, within the
range in which the engaging projection 51 is engaged with the
engaging hole 52, so as to change the relative position with
respect to the support unit 20.
[0053] As shown in FIG. 3, at least one of the engaging holes 52 is
formed in a shape in which three arcs 52a are connected on the
outer circumferential side. Such a configuration allows the
engaging projection 51 to be located so as to be fitted to each arc
52a, thereby facilitating the adjustment of the angle by which the
grinding element 30 is displaced about the rotary shaft 12. The
number of arcs 52a may be set to a desired value not less than two.
The arcs 52a may be formed on the inner circumferential side,
instead of on the outer circumferential side. Alternatively, the
arcs 52a may be omitted, for example, in the case where the
engaging projection 51 is positioned with respect to both ends of
the engaging hole 52. The engaging projection 51 and the engaging
hole 52 constitute an engagement mechanism 50 which makes an
engagement at each of predetermined angular positions so as to
retain the grinding element 30 moved by a predetermined angle in
the circumferential direction. Furthermore, the grinding element 30
and the protrusion/recess-forming member 23 constitute a grinding
implement 2 to be attached, for use, to the base member 24 which is
attached to the rotary shaft 12 driven by the rotary drive unit 11
so as to be rotatable integrally with the rotary shaft 12 and which
has the engaging projections 51 formed on the surface thereof.
[0054] The fixing unit 40 includes a flange portion 41 having a
larger diameter than the through hole 30a of the grinding element
30, and a leg portion 42 integrally formed with the flange portion
41. The leg portion 42 is detachably engaged with the rotary shaft
12, inside the through hole 30a of the grinding element 30, the
through hole 25a of the protrusion/recess-forming member 23, and
the through hole 24a of the base member 24. By the engagement
between the leg portion 42 and the rotary shaft 12, the grinding
element 30 and the support unit 20 composed of the
protrusion/recess-forming member 23 and the base member 24, are
attached to the rotary shaft 12 so as to be rotatable integrally
therewith. In addition, the flange portion 41 presses the grinding
element 30, so that the grinding element 30 is fixed onto the
support unit 20, i.e., the protrusion/recess-forming member 23.
Here, the support unit 20 may be integrally attached to the rotary
shaft 12, by inserting the rotary shaft 12 into the through hole
24a so as to tightly fit the rotary shaft 12 therein.
Alternatively, a female thread may be formed in the through hole
24a and a male thread may be formed on the rotary shaft 12, so that
the support unit 20 can be integrally attached to the rotary shaft
12 by threaded engagement between the female thread and the male
thread.
[0055] In this embodiment, as described above, the protruding
surface portions 21 and the recessed surface portions 22 formed by
the protrusion/recess-forming member 23 are alternately located in
the circumferential direction in the surface of the support unit
20, out of which only the protruding surface portions 21 are in
contact with the grinding element 30. Accordingly, when the
grinding element 30 grinds the work W, the pressure of the grinding
element 30 against the work W concentrates only in the region where
the protruding surface portions 21 are in contact with the grinding
element 30 (indicated by arrows F in FIG. 4), and therefore the
grinding element 30 grinds the work W in the region where the
protruding surface portions 21 are in contact with the grinding
element 30. On the other hand, in the region where the grinding
element 30 opposes the recessed surface portions 22, the grinding
element 30 is in contact with the work W but merely slides on the
surface of the work W without actually grinding the work W.
Therefore, in the region where the protruding surface portions 21
are in contact with the grinding element 30, the abrasive grains
are evenly worn, so that the grinding surface 31, which is
initially uneven, is smoothed.
[0056] However, although the grinding surface 31 is smoothed when
the protruding surface portions 21 and the grinding element 30 have
a first positional relationship as shown in FIG. 4(a), the grinding
element 30 can be displaced in the circumferential direction about
the rotary shaft 12 within the range where the engaging hole 52 is
formed. Therefore, the protruding surface portions 21 and the
grinding element 30 can be set to a second positional relationship
as shown in FIG. 4(b), by loosening or detaching the fixing unit
40, changing the relative position of the grinding element 30 with
respect to the protruding surface portion 21, i.e., the support
unit 20, and again fixing the grinding element 30 by means of the
fixing unit 40. In the region where the protruding surface portions
21 are in contact with the grinding element 30, in the second
positional relationship, which contributes to grinding the work W,
the abrasive grains are not yet worn and the grinding surface 31 is
uneven, and therefore the grinding capability of the grinding
element 30 can be recovered.
[0057] Furthermore, the abrasive grains are worn in different
manners, between the first positional relationship and the second
positional relationship of the protruding surface portions 21 and
the grinding element 30. In addition, in the case of attempting to
reset the positional relationship between the protruding surface
portions 21 and the grinding element 30 to the first positional
relationship, it is practically impossible to accurately reset the
positional relationship to the first positional relationship in a
strict sense, and the positional relationship is surely shifted
therefrom. Therefore, when the grinding capability has declined in
the second positional relationship between the protruding surface
portions 21 and the grinding element 30, projections and recesses
are formed on the grinding surface 31 by resetting the protruding
surface portions 21 and the grinding element 20 to the first
positional relationship, and grinding can be resumed using such
projections and recesses. Changing the position of the grinding
element 30 with respect to the protruding surface portions 21 each
time the grinding capability begins to decline suppresses a drastic
decline in grinding capability, thereby preventing an increase in
friction due to the decline in grinding capability, thus preventing
a grinding burn.
[0058] In this embodiment, moreover, the support unit 20 is
provided with the engaging projections 51, and the grinding element
30 has the engaging holes 52 extending in the circumferential
direction. Such a configuration allows the grinding element 30 to
change the relative position with respect to the support unit 20 to
each predetermined angular position, within the range where the
engaging hole 52 is formed, so that the region of the grinding
element 30 where the grinding surface 31 is uneven can be assuredly
brought into contact with the protruding surface portions 21.
Furthermore, since the protruding surface portions 21 and the
recessed surface portions 22 are formed in the radial pattern in
the surface of the support unit 20, the protruding surface portions
21 and the recessed surface portions 22 can have increased areas,
so that the protruding surface portions 21 are prevented from
chipping from the surface of the support unit 20, which leads to
enhanced safety of the grinding device 1.
[0059] The first embodiment may be modified as follows. FIG. 5
illustrates a first modification of the first embodiment of the
present invention. As shown in FIG. 5, each engaging hole 52 of the
grinding element 30 may be formed in a circular shape having a size
which allows the engaging projection 51 to be engaged with or
disengaged from the engaging hole 52, and a plurality of the
engaging holes 52, six in this modification, may be formed at
predetermined angular positions in the circumferential direction,
respectively, and at the positions in the radial direction where
the engaging holes 52 can be engaged with the respective engaging
projections 51. In addition, the protrusion/recess-forming member
23 may include a flat plate portion 27 provided on the rear surface
of the central portion 25, and the plurality of peripheral portions
26 radially extending from the central portion 25. In this
modification also, the grinding element 30 and the
protrusion/recess-forming member 23 constitute the grinding
implement 2 to be attached, for use, to the base member 24 which is
attached to the rotary shaft 12 driven by the rotary drive unit 11,
so as to be rotatable integrally with the rotary shaft 12 and which
has the engaging projections 51 on the surface thereof.
[0060] The form of the protrusion/recess-forming member 23, i.e.,
the protruding surface portions 21 and the recessed surface
portions 22, is not limited to the form in which the protruding
surface portions 21 and the recessed surface portions 22 are formed
linearly and radially as shown in FIG. 2 and FIG. 5, but may be a
form in which the peripheral portions 26 extend from the central
portion 25 in a curved shape like a windmill as shown in FIG. 6. In
this case also, the peripheral portions 26 of the
protrusion/recess-forming member 23 may form the protruding surface
portions 21, and the portions between the peripheral portions 26
adjacent to each other may form the recessed surface portions
22.
[0061] Furthermore, although the support unit 20 is composed of the
protrusion/recess-forming member 23 and the base member 24, which
are independently formed, in the first embodiment, the support unit
20 may be formed so as to integrally include the protruding surface
portions 21 and the recessed surface portions 22, as a second
modification of the first embodiment shown in FIG. 7. More
specifically, the support unit 20 may be formed by fixing a
plurality of protrusion/recess-forming members 23 in the surface of
the base member 24 at predetermined intervals in the
circumferential direction. In this case, the surface of each
protrusion/recess-forming member 23 constitutes the protruding
surface portion 21, and the surface of the base member 24 where
each protrusion/recess-forming member 23 is not provided
constitutes the recessed surface portion 22. Normally, only a
predetermined region A in the peripheral portion of the grinding
surface 31 (see FIG. 3) of the grinding element 30 is used for the
grinding operation, and therefore, in this embodiment, the
protrusion/recess-forming members 23 are provided over a location
corresponding to the region A when the grinding element 30 is
stacked on the support unit 20. Here, the protrusion/recess-forming
members 23 may be located in the radial pattern as shown in FIG. 2
and FIG. 6, in which case the support unit 20 is formed such that
the protruding surface portions 21 and the recessed surface
portions 22 are formed in the radial pattern. Alternatively, the
support unit 20 may be formed by integrally molding the
protrusion/recess-forming members 23 and the base member 24.
[0062] Forming the support unit 20 so as to integrally include the
protruding surface portions 21 and the recessed surface portions 22
allows the protruding surface portions 21 and the recessed surface
portions 22 to gain flexibility as part of the support unit 20.
Therefore, for example, when the grinding device 1 is used to grind
a curved portion, the support unit 20 assumes a shape that fits the
curved portion, and the work W can be processed more quickly and
cleanly.
[0063] The form of the protruding surface portions 21 and the
recessed surface portions 22 is not limited to the form in which
the protruding surface portions 21 and the recessed surface
portions 22 are located at predetermined intervals in the
circumferential direction as shown in FIG. 7. For example, the
protrusion/recess-forming members 23 shown in FIG. 7 may be formed
in the region A in a circular shape, an elliptical shape, or any
other desired shape as shown in FIG. 8 or FIG. 9, so that the
surface of each protrusion/recess-forming member 23 constitutes the
protruding surface portion 21 and the surface of the base member 24
where each protrusion/recess-forming member 23 is not provided
constitutes the recessed surface portion 22.
[0064] Although the fixing unit 40 is provided to the rotary shaft
12 in the first embodiment, for example, no fixing unit may be
provided to the rotary shaft 12 and the fixing unit 40 may be
provided to each engaging projection 51 as in a third modification
of the first embodiment shown in FIG. 10. Accordingly, the engaging
projections 51 engaged with the engaging holes 52 can be moved in
the circumferential direction along the engaging holes 52 so as to
set the grinding element 30 in position with respect to the support
unit 20, and the grinding element 30 can be fixed to the support
unit 20 by means of the fixing unit 40 with the relative position
of the grinding element 30 with respect to the support unit 20
shifted. As result, the structure of the grinding device 1 can be
simplified.
[0065] Although the fixing unit 40 includes the flange portion 41
and the leg portion 42 in the first embodiment, the configuration
of the fixing unit 40 is not limited to the above configuration.
For example, a hook-and-loop fastener may be attached to the rear
surface of the grinding element 30 (opposite to the grinding
surface 31), and also to the protruding surface portions 21,
thereby constituting the fixing unit 40. Alternatively, an adhesive
capable of bonding the rear surface of the grinding element 30 and
the protruding surface portions 21 to such a degree which allows
separation therebetween, may be employed as the fixing unit 40.
[0066] Furthermore, although the support unit 20 is provided with
the engaging projections 51 and the grinding element 30 has the
engaging holes 52 in the first embodiment and the modifications
thereof, the engaging holes 52 may be provided in the support unit
20, and the engaging projections 51 may be provided to the grinding
element 30. Although the two engaging projections 51 are provided
and also the two engaging holes 52 are provided so as to correspond
to the respective engaging projections 51 in the first embodiment
and the modifications thereof, the number of engaging projections
51 is not limited to two, but may be one, or three or more,
provided that the grinding element 30 is relatively movable with
respect to the support unit 20. In this case, the engaging holes 52
are provided so as to correspond to the engaging projections
51.
[0067] Next, with reference to FIG. 11 to FIG. 13, the grinding
device 1 according to a second embodiment of the present invention
will be described. As shown in FIG. 11, the grinding device 1
includes: the support unit 20 which is attached to the rotary shaft
12 driven by the rotary drive unit 11, so as to be rotatable
integrally with the rotary shaft 12; the grinding element 30 which
is stacked on the support unit 20; and the fixing unit 40 which
fixes the grinding element 30 to the support unit 20. The rotary
drive unit 11 has the same configuration as in the first
embodiment, and therefore the same components are designated by the
same reference numerals and the detailed description thereof is
omitted.
[0068] The support unit 20 includes the base member 24, and the
protrusion/recess-forming member 23 integrally formed on the base
member 24. The base member 24 has a circular shape, in a plan view,
having the same diameter as the grinding element 30, and is formed
such that, in a side view, the peripheral portion is flat while the
central portion is recessed in a cup shape. At the center of the
base member 24 (deepest position of the cup-shaped portion), the
through hole 24a for inserting the rotary shaft 12 therethrough is
formed.
[0069] The protrusion/recess-forming member 23 has a generally
rectangular shape having a length generally equal to the length of
the flat peripheral portion of the base member 24 in the radial
direction. A plurality of such protrusion/recess-forming members 23
are integrally formed on the flat peripheral portion of the base
member 24 at predetermined intervals in the circumferential
direction. In the surface of the support unit 20, the protruding
surface portions 21 which make contact with the rear surface of the
grinding element 30 when in use, and the recessed surface portions
22 recessed from the protruding surface portions 21, are
alternately formed in the circumferential direction, because of the
presence of the protrusion/recess-forming members 23.
[0070] The support unit 20 is formed of, for example, a desired
material such as a metal, a resin, and rubber. As the material for
forming the support unit 20, a material most suitable for the
materials of the grinding element 30 and the work W may be selected
as appropriate.
[0071] The grinding element 30 has a circular shape in a plan view,
and is formed such that, in a side view, the peripheral portion is
flat while the central portion is recessed in a cup shape. The
grinding element 30 includes the uneven grinding surface 31 formed
by the plurality of abrasive grains, located on the surface of the
peripheral portion which is flat in a side view. As the grinding
element 30, for example, a known grindstone, a coated abrasive
product such as a multiple disk and a sanding disk, or a flexible
grinding material such as a non-woven abrasive fabric may be
used.
[0072] As shown in FIG. 11 to FIG. 13, the grinding element 30 has
the through hole 30a formed at the center thereof, and a ratchet
gear 61 is attached to the inner circumference of the through hole
30a. The ratchet gear 61 is formed as an internal gear having a
predetermined pitch in the circumferential direction, and includes
two flange portions 61a extending outward in the radial direction.
Although the details are not illustrated in FIG. 11 to FIG. 13, one
of the two flange portions 61a is integrally formed with the
ratchet gear 61, and the other is formed independently of the
ratchet gear. The ratchet gear 61 is attached to the grinding
element 30 by holding the portion of the grinding element 30 around
the through hole 30a between the two flange portions 61a and
fastening the flange portions 61a together with the mentioned
portion of the grinding element 30 by means of a screw, a clamp, or
the like (not shown). In addition, a bottom portion 61b is provided
on the support unit 20 side of the ratchet gear 61 so as to
protrude inwardly with respect to the tip portion of the ratchet
gear 61.
[0073] The fixing unit 40 includes: the flange portion 41 having a
size which allows the flange portion 41 to fit into the ratchet
gear 61; and the leg portion 42 integrally formed with the flange
portion 41. A female thread (not shown) is formed on the inner
circumferential surface of the leg portion 42, and the fixing unit
40 is attached to the rotary shaft 12 by threadedly engaging the
female thread with a male thread (not shown) formed on the outer
circumferential surface of the rotary shaft 12. When the leg
portion 42 is engaged with the rotary shaft 12, the flange portion
41 presses the bottom portion 61b of the ratchet gear 61, so that
the grinding element 30 is fixed onto the support unit 20. At this
time, the grinding element 30 is fixed to the support unit 20 to
such a degree which allows the grinding element 30 to move in the
circumferential direction. In addition, a male thread (not shown)
is formed on the outer circumferential surface of the leg portion
42, and the base member 24, i.e., the support unit 20, is attached
to the fixing unit 40, i.e., the rotary shaft 12, so as to be
rotatable integrally therewith by threadedly engaging the male
thread on the outer circumferential surface of the leg portion 42
with a female thread (not shown) formed on the inner
circumferential surface of the through hole 24a of the base member
24.
[0074] Four recessed surface portions 43 are formed in the outer
circumferential surface 41a of the flange portion 41 of the fixing
unit 40, and a ratchet pawl 62 is attached in each of the recessed
surface portions 43 with a spring 63 interposed therein. In other
words, the ratchet pawl 62 is attached, via the fixing unit 40, to
the rotary shaft 12 with which the fixing unit 40 is threadedly
engaged. The tip portion of the ratchet pawl 62 is formed so as to
be engageable with the pitch of the ratchet gear 61. The ratchet
gear 61 and the ratchet pawls 62 constitute an engagement mechanism
60 which makes an engagement at each of predetermined angular
positions. Since the engagement mechanism 60 is a ratchet
mechanism, the grinding element 30 which engages with the fixing
unit 40, i.e., the rotary shaft 12, via the engagement mechanism
60, can be made to rotate in one direction (the direction of an
arrow B in FIG. 12). By rotating the grinding element 30 by an
angle corresponding to one pitch of the ratchet gear 61, the
grinding element 30 can be retained by means of the engagement
mechanism 60 in a state where the grinding element 30 has been
moved by a predetermined angle in the circumferential direction.
Here, the number of ratchet pawls 62 is not limited to four, but
may be any number not less than one.
[0075] In this embodiment, the grinding element 30 and the fixing
unit 40 having the engagement mechanism 60 constitute a grinding
implement 3 to be attached, for use, to the support unit 20 which
is attached to the rotary shaft 12 driven by the rotary drive unit
11, so as to be rotatable integrally with the rotary shaft 12 and
which has in the surface thereof the protruding surface portions 21
and the recessed surface portions 22 recessed from the protruding
surface portions 21 alternately located in the circumferential
direction.
[0076] In this embodiment as well, as described above, the
protruding surface portions 21 and the recessed surface portions 22
formed by the protrusion/recess-forming members 23 are alternately
located in the circumferential direction in the surface of the
support unit 20, out of which only the protruding surface portions
21 are in contact with the grinding element 30. By rotating the
grinding element 30 in the direction of the arrow B in FIG. 12, the
relative position of the grinding element 30 with respect to the
support unit 20 can be changed with the engagement mechanism 60, so
that the region where the protruding surface portions 21 are in
contact with the grinding element 30 can be changed. Accordingly,
similar to the first embodiment, changing the position of the
grinding element 30 with respect to the protruding surface portions
21 each time the grinding capability begins to decline suppresses a
drastic decline in grinding capability, thereby preventing an
increase in friction due to the decline in grinding capability,
thus preventing a grinding burn.
[0077] In this embodiment as well, moreover, the relative position
of the grinding element 30 with respect to the support unit 20 can
be changed to each predetermined angular position, so that the
region of the grinding element 30 where the grinding surface 31 is
uneven can be assuredly brought into contact with the protruding
surface portions 21, as in the first embodiment.
[0078] The second embodiment may be modified as follows. Although
the ratchet gear 61 is attached to the grinding element 30 and the
ratchet pawl 62 is attached to the rotary shaft 12 via the fixing
unit 40 in the second embodiment, the ratchet gear 61 may be
attached to the support unit 20, and the ratchet pawl 62 may be
attached directly to the rotary shaft 12, for example. In this
case, the engagement mechanism 60 is provided between the support
unit 20 and the rotary shaft 12, and the support unit 20 is
relatively movable with respect to the grinding element 30.
[0079] Next, with reference to FIG. 14 to FIG. 18, the grinding
device 1 according to a third embodiment of the present invention
will be described. As shown in FIG. 14 and FIG. 15, the grinding
device 1 includes: the support unit 20 which is attached to the
rotary shaft 12 driven by the rotary drive unit 11, so as to be
rotatable integrally with the rotary shaft 12; the grinding element
30 which is stacked on the support unit 20; and the fixing unit 40
which fixes the grinding element 30 to the support unit 20. The
rotary drive unit 11 has the same configuration as in the first
embodiment, and therefore the same components are designated by the
same reference numerals and the detailed description thereof is
omitted.
[0080] The grinding element 30 has a circular shape in a plan view,
and is formed such that, in a side view, the peripheral portion is
flat while the central portion is slightly recessed. The grinding
element 30 has the uneven grinding surface 31 formed by the
plurality of abrasive grains, located on the surface of the
peripheral portion which is flat in a side view. As the grinding
element 30, for example, a known grindstone, a coated abrasive
product such as a multiple disk and a sanding disk, or a flexible
grinding material such as a non-woven abrasive fabric may be
used.
[0081] The grinding element 30 has the through hole 30a formed at
the center thereof for inserting the rotary shaft 12 therethrough.
A guide member 76 is attached to the rear surface of the grinding
element 30, at the position around the through hole 30a. The guide
member 76 has a cylindrical shape, and protruding surface portions
76a and recessed surface portions 76b extending in the axial
direction are formed on the outer circumferential surface of the
guide member 76, so as to be alternately arranged in the
circumferential direction. The guide member 76 is attached to the
grinding element 30 by means of an adhesive, a clamp, a screw, or
the like. The grinding element 30 and the guide member 76
constitute a grinding implement 4 to be attached, for use, to the
support unit 20 which is attached to the rotary shaft 12 driven by
the rotary drive unit 11, so as to be rotatable integrally with the
rotary shaft 12 and which has in the surface thereof the protruding
surface portions 21 and the recessed surface portions 22 recessed
from the protruding surface portions 21 alternately located in the
circumferential direction.
[0082] As shown in FIG. 14 to FIG. 16, a displacement member 77 is
attached to the outer circumference of the guide member 76 so as to
be movable in the axial direction along the guide member 76 but be
restricted from moving in the circumferential direction. More
specifically, the displacement member 77 has, in the inner
circumferential surface thereof, protruding surface portions 77a
and recessed surface portions 77b to be respectively engaged with
the recessed surface portions 76b and the protruding surface
portions 76a formed in the outer circumferential surface of the
guide member 76, and the protruding surface portions 77a and the
recessed surface portions 77b are alternately formed in the
circumferential direction. The protruding surface portions 77a of
the displacement member 77 are engaged with the recessed surface
portions 76b of the guide member 76, and the recessed surface
portions 77b of the displacement member 77 are engaged with the
protruding surface portions 76a of the guide member 76, so that the
displacement member 77 is attached to the guide member 76 so as to
be movable in the axial direction but be restricted from moving in
the circumferential direction. The guide member 76 and the
displacement member 77 constitute a displacement mechanism 75.
[0083] The displacement member 77 includes engaging pins 71
projecting outward in the radial direction from the outer
circumferential surface thereof. It suffices that at least one
engaging pin 71 is provided, and four engaging pins 71 are provided
in this embodiment, at predetermined intervals in the
circumferential direction.
[0084] The support unit 20 includes the base member 24, and the
protrusion/recess-forming member 23 integrally formed on the base
member 24. The base member 24 has a circular shape having the same
diameter as the grinding element 30 in a plan view, and includes a
flat plate-shaped portion 24b formed in the peripheral portion, a
bottomed outer cylindrical portion 24c provided in the central
region of the plate-shaped portion 24b so as to axially extend
toward the rear side, and an inner cylindrical portion 24d provided
inside the outer cylindrical portion 24c so as to extend from the
bottom of the outer cylindrical portion 24c toward the front side.
The outer cylindrical portion 24c has a hole which is formed in the
bottom thereof and communicates with the inner circumferential
surface of the inner cylindrical portion 24d, and a hole defined by
the inner circumferential surface of this hole and the inner
circumferential surface of the inner cylindrical portion 24d
constitutes the through hole 24a through which the rotary shaft 12
can be inserted. A female thread (not shown) is formed in the
through hole 24a, so that the support unit 20 can be attached to
the rotary shaft 12 by threaded engagement between the female
thread and the male thread (not shown) formed on the rotary shaft
12.
[0085] The protrusion/recess-forming member 23 has a generally
rectangular shape having a length generally equal to the length of
the plate-shaped portion 24b of the base member 24 in the radial
direction. A plurality of such protrusion/recess-forming members 23
are integrally formed on the plate-shaped portion 24b of the base
member 24 at predetermined intervals in the circumferential
direction. In the surface of the support unit 20, the protruding
surface portions 21 which make contact with the rear surface of the
grinding element 30 when in use, and the recessed surface portions
22 recessed from the protruding surface portions 21 are alternately
formed in the circumferential direction, because of the presence of
the protrusion/recess-forming members 23.
[0086] As shown in FIG. 17 and FIG. 18, the base member 24 has an
engaging groove 72 formed on the inner circumferential surface of
the outer cylindrical portion 24c throughout the entirety of the
inner circumference thereof, and the engaging groove 72 has a width
which allows insertion of the engaging pin 71 thereinto. The
engaging groove 72 has a plurality of first grooves 72a axially
extending at respective predetermined angular positions, and a
plurality of second grooves 72b connecting between the upper and
the lower end of the first grooves 72a located adjacent to each
other. More specifically, the second grooves 72b are shaped so as
to be inclined downward in the direction opposite to the rotation
direction of the support unit 20 (the direction of an arrow C in
FIG. 17 and FIG. 18). Here, the upward and downward directions are
defined on the basis of the up-down direction in FIG. 17 and FIG.
18, the grinding element 30 side is defined as the upper side, and
the bottom side of the outer cylindrical portion 24c is defined as
the lower side. A sidewall which is located at the lower end
portion of the first groove 72a and where the first groove 72a and
the second groove 72b are connected to each other, constitutes a
stepped portion 72c which is to be engaged with the engaging pin 71
when the grinding device 1 is in use. Since the first groove 72a is
formed at each of the predetermined angular positions, a plurality
of the stepped portions 72c are also provided in the engaging
groove 72 at the respective angular positions. In the case where a
plurality of engaging pins 71 are provided, all of the engaging
pins 71 are provided in the displacement member 77 so as to be
engageable with the stepped portion 72c at each of the
predetermined angular positions. The engaging pin 71 and the
engaging groove 72 constitute an engagement mechanism 70 which
makes an engagement at each of the predetermined angular positions
so as to retain the grinding element 30 moved by a predetermined
angle in the circumferential direction.
[0087] The support unit 20 is formed of, for example, a desired
material such as a metal, a resin, and rubber. As the material for
forming the support unit 20, a material most suitable for the
materials of the grinding element 30 and the work W may be selected
as appropriate.
[0088] The fixing unit 40 includes the flange portion 41 having a
larger diameter than the through hole 30a of the grinding element
30, and the leg portion 42 integrally formed with the flange
portion 41. A male thread (not shown) is formed on the outer
circumferential surface of the leg portion 42.
[0089] As shown in FIG. 16, the displacement member 77 is attached
between the outer cylindrical portion 24c and the inner cylindrical
portion 24d of the support unit 20 attached to the rotary shaft 12.
More specifically, the engaging pin 71 attached to the outer
circumference of the displacement member 77 is detachable by means
of the screw. Accordingly, by positioning the displacement member
77 between the outer cylindrical portion 24c and the inner
cylindrical portion 24d and attaching the engaging pin 71 to the
displacement member 77 via a screw hole (not shown) provided in the
outer cylindrical portion 24c, the displacement member 77 is
attached to the support unit 20, with the engaging pin 71 fitted in
the engaging groove 72 formed in the outer cylindrical portion 24c.
In this state, a spring 78 which biases the displacement member 77
toward the grinding element 30 is provided between the bottom of
the outer cylindrical portion 24c and the displacement member 77.
The spring 78 has a biasing force smaller than a torque generated
when the grinding element 30 described below contacts the work
W.
[0090] The grinding element 30 is attached to the support unit 20
by inserting the guide member 76 into the inner circumference of
the displacement member 77. By threadedly engaging the male thread
on the leg portion 42 of the fixing unit 40 with a female thread
(not shown) of the support unit 20, the flange portion 41 of the
fixing unit 40 is caught by the portion of the grinding element 30
around the through hole 30a, so that the grinding element 30 is
fixed onto the support unit 20. At this time, the grinding element
30 is fixed to the support unit 20 to such a degree which allows
the grinding element 30 to move in the circumferential
direction.
[0091] Next, with reference to FIG. 17 and FIG. 18, the working of
the engagement mechanism 70 and the displacement mechanism 75 to
relatively move the grinding element 30 in the circumferential
direction with respect to the support unit 20, will be described.
Since the support unit 20 is threadedly engaged with the rotary
shaft 12, the support unit 20 is made to rotate in the direction of
the arrow C when the rotary shaft 12 is driven by the rotary drive
unit 11. When the grinding device 1 is used, the grinding element
30 is pressed against the work W, and the grinding element 30 is
subjected to a torque generated owing to the friction with the work
W and imposed in the direction opposite to the rotation direction
of the support unit 20 (the direction of the arrow C). The torque
is transmitted, via the guide member 76 integrally attached to the
grinding element 30, to the displacement member 77 attached to the
guide member 76 so as to be restricted from moving in the
circumferential direction. The torque generated at this time is
greater than the biasing force of the spring 78 biasing the
displacement member 77 toward the grinding element 30, and
therefore the engaging pin 71 attached to the displacement member
77 is moved toward the bottom side of the outer cylindrical portion
24c, against the biasing force of the spring 78. Therefore, the
engaging pin 71 migrates inside the engaging groove 72 toward the
bottom side of the outer cylindrical portion 24c, and in the
direction in which the torque is generated, that is, in the
direction of an arrow D1 in FIG. 18, and comes into engagement with
the stepped portion 72c.
[0092] Since the torque is generated in the direction opposite to
the rotation direction of the support unit 20 (the direction of the
arrow C) while the grinding element 30 is pressed against the work
W, the engaging pin 71 engaged with the stepped portion 72c is
retained as it is, by the torque. Accordingly, the rotation of the
support unit 20 is transmitted via the stepped portion 72c and the
engaging pin 71 to the displacement member 77. Since the protruding
surface portions 77a and the recessed surface portions 77b of the
displacement member 77 are respectively engaged with the recessed
surface portions 76b and the protruding surface portions 76a of the
guide member 76, the rotation of the displacement member 77 is
transmitted to the guide member 76, and to the grinding element 30
integrally attached to the guide member 76, via the guide member
76. Thus, the grinding element 30 grinds the work W.
[0093] When the grinding operation for the work W is finished and
the grinding element 30 is separated from the work W, the grinding
element 30 is no longer subjected to the torque, and the
displacement member 77 is biased toward the grinding element 30 by
the biasing force of the spring 78. Accordingly, the engaging pin
71 migrates inside the engaging groove 72 in the direction of an
arrow E1. At this time, the engaging pin 71 remains in contact with
an upper wall surface 72d of the first groove 72a, because of the
biasing force of the spring 78. When the grinding element 30 is
again pressed against the work W, the grinding element 30 is
subjected to a torque as described above, and the engaging pin 71
migrates inside the engaging groove 72 in the direction of an arrow
D2. Since the displacement member 77 having the engaging pin 71
attached thereto and the guide member 76 attached to the grinding
element 30 are unable to move in the circumferential direction, the
grinding element 30 moves in the circumferential direction by a
predetermined angle with respect to the support unit 20, owing to
the migration of the engaging pin 71 inside the engaging groove 72
in the circumferential direction, i.e., the engaging action of the
engagement mechanism 70.
[0094] As described above, in this embodiment as well, the
protruding surface portions 21 and the recessed surface portions 22
formed by the protrusion/recess-forming member 23 are alternately
located in the circumferential direction in the surface of the
support unit 20, out of which only the protruding surface portions
21 are in contact with the grinding element 30. The relative
position of the grinding element 30 with respect to the support
unit 20 can be changed with the engagement mechanism 70 and the
displacement mechanism 75, so that the region where the protruding
surface portions 21 are in contact with the grinding element 30 can
be changed. Accordingly, similar to the first embodiment,
periodically changing the position of the grinding element 30 with
respect to the protruding surface portions 21 suppresses a drastic
decline in grinding capability, thereby preventing an increase in
friction due to the decline in grinding capability, thus preventing
a grinding burn.
[0095] Furthermore, in this embodiment as well, similar to the
first embodiment, the relative position of the grinding element 30
with respect to the support unit 20 can be changed to each of the
predetermined angular positions, so that the region of the grinding
element 30 where the grinding surface 31 is uneven can be assuredly
brought into contact with the protruding surface portions 21. In
this embodiment, in addition, since the grinding device 1 includes
the displacement mechanism 75, the grinding element 30 can be
automatically moved relative to the support unit 20, without the
need for the user of the grinding device 1 to intentionally move
the grinding element 30 relative to the support unit 20. Therefore,
the user can continue to use the grinding device 1 for a long time,
without worrying about a decline in grinding capability.
[0096] The third embodiment may be modified as follows. In the
third embodiment, the guide member 76 is attached to the grinding
element 30, the displacement member 77 is attached via the guide
member 76, and the engaging pin 71 is further attached via the
displacement member 77, and also the engaging groove 72 is formed
in the support unit 20. However, the engaging groove 72 may be
formed in the grinding element 30, and the guide member 76, the
displacement member 77, and the engaging pin 71 may be attached to
the support unit 20.
[0097] Next, with reference to FIG. 19 to FIG. 21, the grinding
device 1 according to a fourth embodiment of the present invention
will be described. As shown in FIG. 19 and FIG. 20, the grinding
device 1 includes: the support unit 20 which is attached to the
rotary shaft 12 driven by the rotary drive unit 11, so as to be
rotatable integrally with the rotary shaft 12; the grinding element
30 which is stacked on the support unit 20; and the fixing unit 40
which fixes the grinding element 30 to the support unit 20. The
rotary drive unit 11 has the same configuration as in the first
embodiment, and therefore the same components are designated by the
same reference numerals and the detailed description thereof is
omitted.
[0098] The support unit 20 includes the base member 24, and the
protrusion/recess-forming member 23 integrally formed on the base
member 24. The base member 24 has a circular shape, in a plan view,
having the same diameter as the grinding element 30, and is formed
such that, in a side view, the peripheral portion is flat while the
central portion is recessed in a cup shape. At the center of the
base member 24 (deepest position of the cup-shaped portion), the
through hole 24a for inserting the rotary shaft 12 therethrough is
formed, and the portion around the through hole 24a is formed as a
flat bottom portion 24e.
[0099] The protrusion/recess-forming member 23 has a generally
rectangular shape having a length generally equal to the length of
the flat peripheral portion of the base member 24 in the radial
direction. A plurality of such protrusion/recess-forming members 23
are integrally formed on the flat peripheral portion of the base
member 24 at predetermined intervals in the circumferential
direction. In the surface of the support unit 20, the protruding
surface portions 21 which make contact with the rear surface of the
grinding element 30 when in use, and the recessed surface portions
22 recessed from the protruding surface portions 21, are
alternately formed in the circumferential direction, because of the
presence of the protrusion/recess-forming members 23.
[0100] The support unit 20 is formed of, for example, a desired
material such as a metal, a resin, and rubber. As the material for
forming the support unit 20, a material most suitable for the
materials of the grinding element 30 and the work W may be selected
as appropriate.
[0101] The grinding element 30 has a circular shape in a plan view,
and is formed such that, in a side view, the peripheral portion is
flat while the central portion is recessed in a cup shape. The
grinding element 30 has the uneven grinding surface 31 formed by
the plurality of abrasive grains, located on the surface of the
peripheral portion which is flat in a side view. As the grinding
element 30, for example, a known grindstone, a coated abrasive
product such as a multiple disk and a sanding disk, or a flexible
grinding material such as a non-woven abrasive fabric may be
used.
[0102] As shown in FIG. 19 to FIG. 21, the grinding element 30 has
the through hole 30a formed at the center thereof, and a first face
gear 81 is attached to the through hole 30a. The first face gear 81
has a predetermined pitch in the circumferential direction. Two
flange portions 81a are formed so as to extend outward in the
radial direction from the surface of the first face gear 81
opposite to the surface on which the teeth of the first face gear
81 are formed. Although the details are not illustrated in FIG. 19
to FIG. 21, one of the two flange portions 81a is integrally formed
with the first face gear 81, and the other is formed independently
of the first face gear 81. The first face gear 81 is attached to
the grinding element 30 by holding the portion of the grinding
element 30 around the through hole 30a between the two flange
portions 81a and fastening the flange portions 81a together with
the mentioned portion of the grinding element 30 by means of a
screw, a clamp, or the like (not shown). The grinding element 30
and the first face gear 81 constitute a grinding implement 5 to be
attached, for use, to the support unit 20 which is attached to the
rotary shaft 12 driven by the rotary drive unit 11, so as to be
rotatable integrally with the rotary shaft 12 and which has in the
surface thereof the protruding surface portions 21 and the recessed
surface portions 22 recessed from the protruding surface portions
alternately located in the circumferential direction.
[0103] On the bottom portion 24e of the base member 24 of the
support unit 20, a second face gear 82 is provided around the
through hole 24a. The second face gear 82 is provided on the
support unit 20, by being integrally formed with the base member
24, or being attached to the base member 24 with an adhesive, a
screw, a clamp, or the like. The second face gear 82 has a pitch
which allows the second face gear 82 to mesh with the first face
gear 81, in the circumferential direction. The size of the second
face gear 82 in the radial direction is approximately half the size
of the first face gear 81 in the radial direction, and the second
face gear 82 is configured to mesh with the inner portion of the
first face gear 81. The first face gear 81 and the second face gear
82 constitute an engagement mechanism 80 which makes an engagement
at each of predetermined angular positions so as to retain the
grinding element 30 moved by a predetermined angle in the
circumferential direction.
[0104] A third face gear 86 is attached to the outer circumference
of the second face gear 82 so as to be movable in the axial
direction but be restricted from moving in the circumferential
direction. The third face gear 86 has a pitch which allows the
third face gear 86 to mesh with the first face gear 81, in the
circumferential direction. In addition, the third face gear 86 has
an inner diameter which allows the second face gear 82 to be fitted
therein, and an outer diameter generally equal to that of the first
face gear 81. Thus, the third face gear 86 is configured to mesh
with the outer portion of the first face gear 81.
[0105] Legs 87 extending in the axial direction are provided on the
surface of the third face gear 86 opposite to the surface on which
the teeth of the third face gear 86 are formed. The legs 87 each
have a size which allows the leg 87 to fit into a hole 24f formed
in the bottom portion 24e of the base member 24. The third face
gear 86 is attached to the base member 24 of the support unit 20 by
fitting the second face gear 82 to the inner circumferential
surface of the third face gear 86 and inserting the legs 87 to the
respective holes 24f in the bottom portion 24e of the base member
24. In this state, a spring 88 which biases the third face gear 86
toward the grinding element 30 is provided between the third face
gear 86 and the bottom portion 24e. The spring 88 has such a
biasing force that prevents the legs 87 of the third face gear 86
from coming out of the holes 24f. Since the legs 87 are prevented
from coming out of escaping from the hole 24f, the third face gear
86 is restricted from moving in the circumferential direction with
respect to the second face gear 82.
[0106] In addition, the third face gear 86 is configured such that:
the tip portion of the teeth is located on the bottom portion 24e
side with respect to the tip portion of the teeth of the second
face gear 82, when the legs 87 are fitted in the holes 24f, i.e.,
when the third face gear 86 reaches a farthest position toward the
bottom portion 24e of the support unit 20; and the tip portion of
the teeth is located on the grinding element 30 side with respect
to the tip portion of the teeth of the second face gear 82, when
the third face gear 86 reaches a farthest position toward the
grinding element 30 owing to the biasing force of the spring 88.
Furthermore, the third face gear 86 is attached such that the
position of the teeth is deviated in the circumferential direction,
with respect to the second face gear 82. The third face gear 86
constitutes a displacement mechanism 85.
[0107] The fixing unit 40 includes the flange portion 41 having a
diameter larger than the inner diameter of the first face gear 81,
and the leg portion 42 integrally formed with the flange portion
41. A female thread (not shown) is formed on the inner
circumferential surface of the leg portion 42, and the fixing unit
40 is attached to the rotary shaft 12 by threadedly engaging the
female thread with a male thread (not shown) formed on the outer
circumferential surface of the rotary shaft 12. When the leg
portion 42 is engaged with the rotary shaft 12, the flange portion
41 can make contact with the first face gear 81, so that the
grinding element 30 is retained on the support unit 20 so as to be
restricted from being detached therefrom. At this time, the
grinding element 30 is movable both in the axial direction and in
the circumferential direction. In addition, a male thread (not
shown) is formed on the outer circumferential surface of the leg
portion 42, and the base member 24, i.e., the support unit 20, is
attached to the fixing unit 40, i.e., the rotary shaft 12, so as to
be rotatable integrally therewith by threadedly engaging the male
thread on the outer circumferential surface of the leg portion 42
with a female thread (not shown) formed on the inner
circumferential surface of the through hole 24a of the base member
24.
[0108] Next, with reference to FIG. 22 and FIG. 23, the working of
the engagement mechanism 80 and the displacement mechanism 85 to
relatively move the grinding element 30 in the circumferential
direction with respect to the support unit 20, will be described.
FIG. 22 and FIG. 23 are schematic drawings for explaining the
operation of the first face gear 81 to the third face gear 86 of
the grinding device 1 according to this embodiment. The first face
gear 81, the second face gear 82, and the third face gear 86
operate in the order of FIG. 22(a), FIG. 22(b), FIG. 22(c), FIG.
23(a), FIG. 23(b), and FIG. 23(c), so that the meshing position
between the first face gear 81 and the second face gear 82 is
shifted in the circumferential direction. The details are as
follows.
[0109] Since the support unit 20 is attached to the rotary shaft 12
via the fixing unit 40 so as to be rotatable integrally with the
rotary shaft 12, the support unit 20 is made to rotate when the
rotary shaft 12 is driven by the rotary drive unit 11. When the
grinding device 1 is used, the grinding element 30 is pressed
against the work W, and the third face gear 86 is moved toward the
bottom portion 24e (toward the rotary drive unit 11 side) against
the biasing force of the spring 88. At this time, the first face
gear 81 and the second face gear 82 are meshed with each other as
shown in FIG. 22(a), so that the rotation of the support unit 20 is
transmitted via the second face gear 82 and the first face gear 81
to the grinding element 30. Thus, the grinding element 30 grinds
the work W.
[0110] When the grinding operation for the work W is finished and
the grinding element 30 is separated from the work W, the grinding
element 30 is released from the pressing force exerted toward the
bottom portion 24e of the support unit 20, and therefore the third
face gear 86 is biased toward the grinding element 30 by the
biasing force of the spring 88. Accordingly, the third face gear 86
lifts the first face gear 81 as shown in FIG. 22(b). When the third
face gear 86 lifts the first face gear 81, the first face gear 81
is disengaged from the second face gear 82. At this time, since the
teeth of the second face gear 82 and the teeth of the third face
gear 86 are deviated in the circumferential direction, the first
face gear 81 moves in the circumferential direction along the third
face gear 86 so as to be meshed with the third face gear 8, as
shown in FIG. 22(c).
[0111] When the grinding element 30 is again pressed against the
work W, the grinding element 30 is pressed toward the bottom
portion 24e of the support unit 20, and the third face gear 86
moves toward the bottom portion 24e (toward the rotary drive unit
11 side) against the biasing force of the spring 88. Accordingly,
as shown in FIG. 23(a), the first face gear 81 and the second face
gear 82 are meshed with each other. When the grinding element 30 is
further pressed toward the support unit 20, the first face gear 81
is disengaged from the third face gear 86, and then meshed with the
second face gear 82, and moves in the circumferential direction
along the teeth of the second face gear 82, as shown in FIG. 23(b).
Therefore, the first face gear 81 is meshed with the second face
gear 82 at the position shifted by one pitch in the circumferential
direction, as shown in FIG. 23(c). Consequently, the grinding
element 30 is moved by a predetermined angle in the circumferential
direction with respect to the support unit 20 owing to the engaging
action of the displacement mechanism 85 (the third face gear 86)
and the engagement mechanism 80 (the first face gear 81 and the
second face gear 82).
[0112] As described above, in this embodiment as well, the
protruding surface portions 21 and the recessed surface portions 22
formed by the protrusion/recess-forming members 23 are alternately
located in the circumferential direction in the surface of the
support unit 20, out of which only the protruding surface portions
21 are in contact with the grinding element 30. The relative
position of the grinding element 30 with respect to the support
unit 20 can be changed with the engagement mechanism 80 and the
displacement mechanism 85, so that the region where the protruding
surface portions 21 are in contact with the grinding element 30 can
be changed. Accordingly, similar to the first embodiment,
periodically changing the position of the grinding element 30 with
respect to the protruding surface portions 21 suppresses a drastic
decline in grinding capability, thereby preventing an increase in
friction due to the decline in grinding capability, thus preventing
a grinding burn.
[0113] Furthermore, in this embodiment as well, similar to the
first embodiment, the relative position of the grinding element 30
with respect to the support unit 20 can be changed to each of the
predetermined angular positions, so that the region of the grinding
element 30 where the grinding surface 31 is uneven can be assuredly
brought into contact with the protruding surface portions 21. In
addition, similar to the third embodiment, since the grinding
device 1 includes the displacement mechanism 85, the grinding
element 30 can be automatically moved relative to the support unit
20, without the need for the user of the grinding device 1 to
intentionally move the grinding element 30 relative to the support
unit 20. Therefore, the user can continue to use the grinding
device 1 for a long time, without worrying about a decline in
grinding capability.
[0114] The fourth embodiment may be modified as follows. Although
the first face gear 81 is attached to the grinding element 30, and
the second face gear 82 is attached to the support unit 20 in the
fourth embodiment, the second face gear 82 may be attached to the
grinding element 30, and the first face gear 81 may be attached to
the support unit 20. In this case, the third face gear 86 may be
attached to the outer circumference of the second face gear 82,
i.e., the grinding element 30.
[0115] Although some embodiments of the present invention have been
described above, the present invention is not limited to those
embodiments, and various modifications may be made without
departing from the gist of the present invention.
[0116] For example, the support unit 20 and the grinding element 30
are not limited to those in each of the embodiments and may be
configured as in any of other embodiments and modifications. To
cite one example, the support unit 20 and the grinding element 30
according to the second embodiment, the third embodiment, or the
fourth embodiment may be adopted as the support unit 20 and the
grinding element 30 according to the first embodiment.
[0117] Although the grinding element 30 has a disk shape in the
first embodiment to the fourth embodiment, the grinding element 30
may be formed in a desired shape such as a rectangular plate shape,
a polygonal plate shape, and an elliptical plate shape. The plate
shape in this case includes not only a flat plate having no recess,
but also such a shape in which the central portion is recessed.
[0118] Furthermore, the protruding surface portions 21 are elevated
from the recessed surface portions 22 generally parallel to the
axial direction of the rotary shaft 12, as shown in FIG. 4, in the
first embodiment to the fourth embodiment. Instead, for example,
the protruding surface portions 21 may be elevated from the
recessed surface portions 22 with an inclination of a predetermined
angle, with respect to the axial direction of the rotary shaft 12,
so as to present a trapezoidal shape in a front view, as shown in
FIG. 24. In addition, it is not necessary to form the protruding
surface portions 21 and the recessed surface portions 22 as flat
surfaces, and the protruding surface portions 21 and the recessed
surface portions 22 may be formed of a continuous curved surface,
so as to present a wave shape in a front view, as shown in FIG.
25.
DESCRIPTION OF REFERENCE NUMERALS
[0119] 1 grinding device [0120] 2 grinding implement [0121] 3
grinding implement [0122] 4 grinding implement [0123] 5 grinding
implement [0124] 11 rotary drive unit [0125] 12 rotary shaft [0126]
20 support unit [0127] 21 protruding surface portion [0128] 22
recessed surface portion [0129] 23 protrusion/recess-forming member
[0130] 24 base member [0131] 26a attachment hole [0132] 30 grinding
element [0133] 31 grinding surface [0134] 40 fixing unit [0135] 50
engagement mechanism [0136] 51 engaging projection [0137] 52
engaging hole [0138] 60 engagement mechanism [0139] 61 ratchet gear
[0140] 62 ratchet pawl [0141] 70 engagement mechanism [0142] 71
engaging pin [0143] 72 engaging groove [0144] 72c stepped portion
[0145] 75 displacement mechanism [0146] 76 guide member [0147] 77
displacement member [0148] 80 engagement mechanism [0149] 81 first
face gear [0150] 82 second face gear [0151] 85 displacement
mechanism [0152] 86 third face gear
* * * * *