U.S. patent application number 12/448814 was filed with the patent office on 2010-02-18 for fixing device for rotary blade.
This patent application is currently assigned to Makita Corporation. Invention is credited to Yoichiro Koike, Yuji Takahashi.
Application Number | 20100040474 12/448814 |
Document ID | / |
Family ID | 39608533 |
Filed Date | 2010-02-18 |
United States Patent
Application |
20100040474 |
Kind Code |
A1 |
Takahashi; Yuji ; et
al. |
February 18, 2010 |
FIXING DEVICE FOR ROTARY BLADE
Abstract
A fixing device for fixing a rotary blade to a spindle in a
bench circular saw, for example, has a structure in which it is
difficult to achieve structural compactification in radial size.
Therefore, there has been a problem of sacrificing an inclination
angle and a cutting depth of the rotary blade. Provided is a fixing
device free from such problems owing to employment of a structure
which can be easily compactified in a radial direction. Cam
portions are provided on respective surfaces opposite to each other
of an intermediate flange and an outer flange so as to mesh with
each other. The cam portions slide with each other with a
rotational force imparted to the rotary blade so that the
rotational force is converted into a displacement in a direction of
an axis of the intermediate flange and is applied in a direction of
clamping the rotary blade.
Inventors: |
Takahashi; Yuji; (Anjo-shi,
JP) ; Koike; Yoichiro; (Anjo-shi, JP) |
Correspondence
Address: |
OLIFF & BERRIDGE, PLC
P.O. BOX 320850
ALEXANDRIA
VA
22320-4850
US
|
Assignee: |
Makita Corporation
Anjo-shi
JP
|
Family ID: |
39608533 |
Appl. No.: |
12/448814 |
Filed: |
December 19, 2007 |
PCT Filed: |
December 19, 2007 |
PCT NO: |
PCT/JP2007/074419 |
371 Date: |
July 22, 2009 |
Current U.S.
Class: |
416/219R |
Current CPC
Class: |
B27B 5/38 20130101; B27B
5/32 20130101; B24B 45/006 20130101 |
Class at
Publication: |
416/219.R |
International
Class: |
F01D 5/30 20060101
F01D005/30 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 9, 2007 |
JP |
2007-001247 |
Claims
1. A device for fixing a rotary blade to a rotation fixing portion
of a rotatable spindle, comprising: an inner flange and an outer
flange fixing the rotary blade to the rotation fixing portion with
respect to the rotation by clamping the rotary blade from both
sides thereof; and a fixing flange producing, with respect to the
inner flange and the outer flange, a clamping force against the
rotary blade in a direction of an axis of the spindle by tightening
a fixing screw portion into an end surface of the rotation fixing
portion; wherein the fixing device further comprises: an
intermediate flange interposed between the rotary blade and the
outer flange; a cam meshing portion provided between the
intermediate flange and the outer flange paired therewith, the cam
meshing portion being constituted by meshing of cam portions
varying in height in the direction of the axis of the spindle; a
member serving as the outer flange and paired with the intermediate
flange so as to constitute the cam meshing portion, fixed to the
rotation fixing portion with respect to the rotation; and by
rotational resistance imparted to the rotary blade, the
intermediate flange is rotated relative to the member paired with
the intermediate flange for constituting the cam meshing portion,
so that an axial force in the direction of the axis of the spindle
is produced in the cam meshing portion.
2. The fixing device according to claim 1, wherein: the fixing
device is provided with the inner flange fixed to the rotation
fixing portion with respect to the rotation and contacting with an
end portion of the rotation fixing portion so as to be restricted
in displacement in the direction of the axis of the spindle; the
intermediate flange clamps the rotary blade between the
intermediate flange and the inner flange and rotatable relative to
the rotation fixing portion; the outer flange clamping the
intermediate flange between the outer flange and the rotary blade
and fixed to the rotation fixing portion with respect to the
rotation; the fixing flange clamping the outer flange between the
fixing flange and the intermediate flange and threadably coupled
immovably in the direction of the axis of the spindle by tightening
the fixing thread portion into the end surface of the rotation
fixing portion; the cam meshing portion is provided between the
intermediate flange and the outer flange; and a relative rotational
force relative to the outer flange, which is imparted to the
intermediate flange via the rotary blade, is converted via the cam
meshing portion into a pressing force of the intermediate flange in
the direction of the axis of the spindle against the rotary
blade.
3. The fixing device according to claim 2, wherein frictional
resistance in a rotational direction of the intermediate flange
relative to the rotary blade is set to be higher than sliding
resistance of the cam portions.
4. The fixing device according to claim 2, wherein a friction
reducing means is interposed between the rotary blade and the inner
flange, for reducing frictional resistance in a rotational
direction of the inner flange against to the rotary blade in
comparison with the frictional resistance in the rotational
direction of the intermediate flange against the rotary blade.
5. The fixing device according to claim 2, wherein the inner flange
is rotatably attached to the rotation fixing portion of the
spindle.
6. The fixing device according to claim 2, wherein: a cover is
attached between the intermediate flange and the outer flange so as
to cover peripheries thereof; the cover is imparted with an elastic
force in the rotational direction and is engaged with the
intermediate flange and the outer flange in the rotational
direction; and regarding a position of the intermediate flange in
the rotational direction relative to the outer flange, biasing is
made toward an initial position at which the cam portions of the
intermediate flange and the cam portions of the outer flange mesh
most deeply with each other.
7. The fixing device according to claim 2, wherein, regarding a
position of the intermediate flange in the rotational direction
relative to the spindle, an initial position biasing means is
interposed between the intermediate flange and the rotation fixing
portion of the spindle, for biasing toward an initial position at
which the cam portions of the intermediate flange and the cam
portions of the outer flange mesh most deeply with each other.
8. (canceled)
9. (canceled)
10. A device for fixing a rotary blade to a rotation fixing portion
of a rotatable spindle, comprising: an inner flange and an outer
flange fixing the rotary blade to the rotation fixing portion with
respect to the rotation by clamping the rotary blade from both
sides thereof; and a fixing flange producing, with respect to the
inner flange and the outer flange, a clamping force against the
rotary blade in a direction of an axis of the spindle by tightening
a fixing screw portion into an end surface of the rotation fixing
portion; wherein the fixing device further comprises: an
intermediate flange interposed between the rotary blade and the
inner flange; a cam meshing portion provided between the
intermediate flange and the inner flange paired therewith, the cam
meshing portion being constituted by meshing of cam portions
varying in height in the direction of the axis of the spindle; a
member serving as the inner flange and paired with the intermediate
flange so as to constitute the cam meshing portion, fixed to the
rotation fixing portion with respect to the rotation; and by
rotational resistance imparted to the rotary blade, the
intermediate flange is rotated relative to the member paired with
the intermediate flange for constituting the cam meshing portion,
so that an axial force in the direction of the axis of the spindle
is produced in the cam meshing portion.
11. The fixing device according to claim 10, wherein: the inner
flange is fixed to the rotation fixing portion with respect to the
rotation and contacting with an end portion of the rotation fixing
portion so as to be restricted in displacement in the direction of
the axis of the spindle; the intermediate flange is clamped between
the inner flange and the rotary blade and is allowed to be rotated
relative to the rotation fixing portion; the outer flange clamps
the rotary blade between the outer flange and the intermediate
flange and fixed to the rotation fixing portion with respect to the
rotation; the fixing flange clamps the outer flange between the
fixing flange and the rotary blade and threadably coupled immovably
in the direction of the axis of the spindle by tightening the
fixing thread portion into the end surface of the rotation fixing
portion; the cam meshing portion is provided between the inner
flange and the intermediate flange; and a relative rotational force
relative to the inner flange, which is imparted to the intermediate
flange via the rotary blade, is converted via the cam meshing
portion into a pressing force of the intermediate flange in the
direction of the axis of the spindle against the rotary blade.
12. The fixing device according to claim 11, wherein frictional
resistance in a rotational direction of the intermediate flange
relative to the rotary blade is set to be higher than sliding
resistance of the cam portions.
13. The fixing device according to claim 11, wherein, regarding a
position of the intermediate flange in the rotational direction
relative to the spindle, an initial position biasing means is
interposed between the intermediate flange and the rotation fixing
portion of the spindle, for biasing toward an initial position at
which the cam portions of the intermediate flange and the cam
portions of the inner flange mesh most deeply with each other.
14. A device for fixing a rotary blade to a rotation fixing portion
of a rotatable spindle, comprising: an inner flange fixed to the
rotation fixing portion with respect to the rotation and contacting
with an end portion of the rotation fixing portion so as to be
restricted in displacement in the direction of the axis of the
spindle; an inner intermediate flange clamped between the inner
flange and the rotary blade and allowed to be rotated relative to
the rotation fixing portion; an outer intermediate flange clamping
the rotary blade between the outer intermediate flange and the
inner intermediate flange and allowed to be rotated relative to the
rotation fixing portion; an outer flange clamping the outer
intermediate flange between the outer flange and the rotary blade
and fixed to the rotation fixing portion with respect to the
rotation; a fixing flange clamping the outer flange between the
fixing flange and the outer intermediate flange and threadably
coupled immovably in the direction of the axis of the spindle by
tightening the fixing thread portion into the end surface of the
rotation fixing portion; and cam meshing portions varying in height
in the direction of the axis of the spindle mesh with each other,
respectively provided between the inner flange and the inner
intermediate flange and between the outer flange and the outer
intermediate flange, wherein relative rotational forces relative to
the inner flange and the outer flange, which are imparted to the
inner intermediate flange and the outer intermediate flange via the
rotary blade, are converted via the cam meshing portions
constituted by the two sets of the cam portions into pressing
forces of the inner intermediate flange and the outer intermediate
flange in the direction of the axis of the spindle against the
rotary blade.
15. The fixing device according to claim 14, wherein frictional
resistance in a rotational direction of the outer intermediate
flange relative to the rotary blade is set to be higher than
sliding resistance of the cam portions provided between the outer
flange and the outer intermediate flange.
16. The fixing device according to claim 14, wherein: a cover is
attached between the outer intermediate flange and the outer flange
so as to cover peripheries thereof; the cover is imparted with an
elastic force in the rotational direction and is engaged with the
outer intermediate flange and the outer flange in the rotational
direction; and regarding a position of the outer intermediate
flange in the rotational direction relative to the outer flange,
biasing is made toward an initial position at which the cam
portions of the outer intermediate flange and the cam portions of
the outer flange mesh most deeply with each other.
17. The fixing device according to claim 14, wherein, regarding a
position of the outer intermediate flange in the rotational
direction relative to the spindle, an initial position biasing
means is interposed between the outer intermediate flange and the
rotation fixing portion of the spindle, for biasing toward an
initial position at which the cam portions of the outer
intermediate flange and the cam portions of the outer flange mesh
most deeply with each other.
Description
TECHNICAL FIELD
[0001] The present invention relates to a fixing device, for
example, for attaching a circular cutting blade (rotary blade) to a
spindle in a portable circular saw and to a tool-less type fixing
device which can easily be fastened by a manual manipulation and
which can reliably prevent slippage (relative rotation) of the
rotary blade relative to the spindle during use thereof.
BACKGROUND ART
[0002] One conventional example of the tool-less type fixing device
allowing an operator to attach and detach, without use of special
tools, a circular rotary blade to the leading end of a spindle
rotated by a drive motor is disclosed in Japanese Laid-Open Patent
Publication No. 2001-96407. The conventional fixing device is
constructed to have a ratchet mechanism for engaging and
disengaging meshing of teeth with recessed portions on the outer
peripheral side by displacing claw portions in a radial direction
thereof.
[0003] In addition, as an alternative, there has been provided a
fixing device which can be firmly fastened by a manual manipulation
owing to a structure incorporating therein a planetary gear train
for speed reduction.
[0004] Patent Document 1: Japanese Laid-Open Patent Publication No.
2001-96407
DISCLOSURE OF THE INVENTION
Problems to be Solved by the Invention
[0005] However, many of those conventional fixing devices have
relatively large diameters because it is structurally difficult to
achieve compactification in its radial direction. Therefore, there
has been a problem in that the conventional fixing devices cannot
be applied directly to, for example, portable circular saws.
Regarding the portable circular saws, in a case of performing
oblique cutting in which cutting blades are inclined and obliquely
cut into materials to be subjected to cutting, for the purpose of
enabling oblique cutting at large angles while avoiding
interference of the fixing device with the materials to be
subjected to cutting, it is desirable that the sizes in the radial
and axial directions of the fixing device are as small as possible.
Further, in the portable circular saws, when a fixing device having
a large diameter is mounted to a center of the rotary blade, an
upper limit of a cutting depth of the rotary blade with respect to
the materials to be subjected to cutting is lowered. In this regard
also, it was difficult to apply the conventional fixing devices
directly to the cutting machines of this type.
[0006] Under the circumstances, the present invention has been made
for the purpose of providing a fixing device for a rotary blade,
with which the rotary blade can be firmly fixed by a manual
manipulation, in which slippage of the rotary blade relative to a
spindle is not caused owing to cutting resistance or at a time of
braking, and which is compact in a radial direction thereof and
consequently can easily be applied to a circular saw capable of
performing the oblique cutting.
Means for Solving the Problems
[0007] Thus, the present invention provides a fixing device having
structures described in respective claims.
[0008] According to a fixing device as described in claim 1, when
rotational resistance such as cutting resistance is imparted to a
rotary blade, a relative rotational force is imparted between an
intermediate flange and an inner flange or an outer flange, and the
relative rotational force is converted into an axial force in a
direction of an axis of a spindle via a cam meshing portion. The
axial force is added to a clamping force of a fixing flange. As a
result, the rotary blade is more firmly clamped between the inner
flange and the outer flange, thereby being fixed more firmly to the
spindle with respect to the rotation. Thus, it is only necessary
for a user to lightly tighten the fixing flange at the time of
mounting the rotary blade.
[0009] When no rotational resistance is not imparted to the rotary
blade, the relative rotational force of the intermediate flange to
the inner flange or the outer flange is not imparted. As a result,
the axial force of the cam meshing portion is eliminated, and hence
the fixing flange can be easily loosened.
[0010] As described above, the axial force produced in the cam
meshing portion provided between the intermediate flange and the
inner flange or the outer flange is utilized. Therefore, the rotary
blade can be more firmly fixed without impairing compactness in the
radial direction of the spindle, and eventually, can be easily
applied to a circular saw or the like provided with a function of
oblique cutting.
[0011] According to a fixing device as described in claim 2, the
rotational resistance against the rotary blade acts as an external
force for displacing the rotary blade in the rotational direction
relative to the spindle (rotational force, hereinafter also simply
referred to as rotational resistance). Meanwhile, the inner flange
is fixed to the rotation fixing portion with respect to the
rotation, and the intermediate flange is mounted to the rotation
fixing portion so as to be relatively rotatable. Thus, the
rotational resistance imparted to the rotary blade acts as a
rotational force for rotating the intermediate flange with respect
to the spindle. Owing to the rotational resistance, when being
displaced in the rotational direction relative to the spindle, the
intermediate flange is displaced in the rotational direction
relative to the outer flange whose rotation is restricted by the
rotation fixing portion. When the intermediate flange is displaced
in the rotational direction relative to the outer flange,
displacements of cam portions thereof in the circumferential
direction (sliding operation) are produced. With this, the
rotational resistance partially acts on the intermediate flange as
a force component (axial force) in the direction of the axis of the
spindle, and acts on the intermediate flange as a pressing force to
the rotary blade.
[0012] As described above, when high rotational resistance at the
time of working or high inertia at the time of braking (hereinafter
also simply referred to as rotational resistance) is imparted to
the rotary blade, the rotational resistance or the like is
partially converted via the sliding operation between the cam
portions of the intermediate flange and the cam portions of the
outer flange into an axial force for pressing the intermediate
flange against the rotary blade. As a result, slippage in the
rotational direction of the rotary blade relative to the inner
flange can be prevented. With this, when a user manually couples
the fixing flange with respect to the spindle by screwing, the
rotational force of the rotary blade relative to the spindle is
converted into the axial force for pressing the rotary blade toward
the inner flange in the fixing device. With this, slippage of the
rotary blade can be prevented. Therefore, it is possible to
reliably prevent slippage of the rotary blade without impairing
conventional operability.
[0013] Further, the axial force is produced by the sliding
operation of the cam portions provided on the surfaces opposed to
each other of the intermediate flange and the outer flange, and the
clamping force of the rotary blade between the inner flange and the
intermediate flange is increased by the axial force. Unlike the
conventional methods, the movement in the radial direction of the
spindle is not utilized, and hence the size in the radial direction
of the fixing device is more easily compactified in comparison with
that of conventional ones. The sizes in the radial direction and
the axial direction of the spindle of the fixing device are
compactified, whereby it is possible to set the inclination angle
of the rotary blade of a portable circular saw at the time of
oblique cutting to be large, and also possible to set the cutting
depth into the material subjected to cutting to be large.
Accordingly, the fixing device can be easily applied to the
portable circular saw or the like.
[0014] According to a fixing device as described in claim 3, in
addition to the above-mentioned operation and effects, the
rotational force of the rotary blade (inertia at the time of
activation or stopping and rotational resistance at the time of
processing) is reliably transmitted to the intermediate flange so
that the sliding operation of the cam portions can be efficiently
produced. With this, it is possible to efficiently increase the
pressing force of the intermediate flange to the rotary blade.
[0015] The frictional resistance of the intermediate flange
relative to the rotary blade can be properly set based on materials
thereof and an average diameter in the contact area. Further,
inversely, a lubricant is interposed or applied between the cam
surfaces of the cam portions, or the inclination angle of the cam
surface is properly set, whereby the sliding resistance of the cam
portions is reduced as much as possible in comparison with the
frictional resistance of the intermediate flange relative to the
rotary blade.
[0016] According to a fixing device as described in claim 4, when
no rotational resistance is not imparted to the rotary blade, the
intermediate flange having the cam portions and the rotary blade
are more easily displaced in the rotational direction relative to
the inner flange, and eventually, to the spindle. With this, the
cam portions are reliably restored to an initial position of
meshing most deeply with each other, and a screw coupling force
(screwing force) of the fixing flange to the spindle is weakened.
As a result, it is possible to easily loosen the fixing flange with
a small rotational manipulating force.
[0017] According to a fixing device as described in claim 5, the
inner flange is fixed to the rotation fixing portion of the spindle
with a play within a predetermined angular range. Therefore, the
displacement of the intermediate flange relative to the rotation
fixing portion is more easily obtained at the time no rotational
resistance is not imparted to the rotary blade. With this, the
fixing device smoothly shifts to a state in which the cam portions
of the intermediate flange and the cam portions of the outer flange
mesh most deeply with each other, whereby the screw coupling force
of the fixing flange is reliably loosened.
[0018] According to a fixing device as described in claim 6, at the
time no rotational resistance is not imparted to the rotary blade,
the cam portions of the intermediate flange and the cam portions of
the outer flange are reliably restored to the initial position
(position of meshing most deeply with each other) by an elastic
force of the cover. Therefore, the screw coupling force of the
fixation flange is reliably loosened.
[0019] According to a fixing device as described in claim 7, at the
time no rotational resistance is not imparted to the blade, the
intermediate flange is restored to the initial position by an
initial position biasing means, and the fixing device can be
reliably shifted so that the cam portions of the intermediate
flange and the cam portions of the outer flange mesh most deeply
with each other. With this, the screw coupling force of the fixing
flange relative to the spindle is loosened, whereby the fixing
flange can be easily loosened with a small force in the case of
replacing the rotary blade or the like.
[0020] According to a fixing device as described in claim 8, when
the cam meshing portion is positioned on the side (inner flange
side) opposite to that in the structure described in claim 2
relative to the rotary blade, the same operation and effects as
those in the case of the structure described in claim 2 can also be
obtained. Also in the fixing device described in claim 8, at the
time no rotational resistance is imparted to the rotary blade, the
intermediate flange is reliably displaced in the rotational
direction. Thus, the fixing device reliably shifts to the state
(initial state) in which the cam portions of the intermediate
flange and the cam portions of the inner flange mesh most deeply
with each other. With this, it is possible to reliably loosen the
screw coupling force of the fixing flange relative to the spindle,
thereby possible to easily loosen the fixing flange with a small
rotational manipulating force.
[0021] According to a fixing device as described in claim 9, the
cam meshing portions are arranged on both sides relative to the
rotary blade. Thus, the displacements of an inner intermediate
flange and an outer intermediate flange in the direction of the
axis of the spindle approximately double, the deepest meshing with
the cam portions occurring at the time no rotational resistance is
imparted to the rotary blade. Therefore, the screw coupling force
of the fixing flange relative to the spindle can be loosened more
reliably. Also in the fixing device described in claim 9, at the
time no rotational resistance is imparted to the rotary blade, the
inner intermediate flange and the outer intermediate flange are
more easily displaced in the rotational directions. Accordingly, it
is ensured that the cam portions shift to a state of meshing most
deeply with each other, whereby the screw coupling force of the
fixing flange relative to the spindle can be loosened.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] FIG. 1 is a vertical sectional view of a fixing device
according to a first embodiment, for illustrating a state of a
rotary blade fixed to a spindle by means of the fixing device.
[0023] FIG. 2 is an exploded view of the fixing device according
the first embodiment.
[0024] FIG. 3 is a view taken from the direction of arrows
(III)-(III) of FIG. 2, and is a plan view of an intermediate
flange.
[0025] FIG. 4 is a sectional view taken along arrows (IV)-(IV) of
FIG. 3, and is a developed view of cam portions of the intermediate
flange.
[0026] FIG. 5 is a view taken from the direction of the arrows
(V)-(V) of FIG. 2, and is a plan view of an outer flange.
[0027] FIG. 6 is a plan view of a fixing flange.
[0028] FIG. 7 is a vertical sectional view of a fixing device
according to a second embodiment, for illustrating the state of the
rotary blade fixed to the spindle by means of the fixing
device.
[0029] FIG. 8 is a horizontal sectional view of a fixing device
according to a third embodiment, for illustrating the state of the
rotary blade fixed to the spindle by means of the fixing
device.
[0030] FIG. 9 is a vertical sectional view of a fixing device
according to a fourth embodiment, for illustrating the state of the
rotary blade fixed to the spindle by means of the fixing
device.
[0031] FIG. 10 is a vertical sectional view of a fixing device
according to a fifth embodiment, for illustrating the state of the
rotary blade fixed to the spindle by means of the fixing
device.
[0032] FIG. 11 is a vertical sectional view of a fixing device
according to a sixth embodiment, for illustrating the state of the
rotary blade fixed to the spindle by means of the fixing
device.
[0033] FIG. 12 is a sectional view taken along arrows (XII)-(XII)
of FIG. 11, and is a horizontal sectional view of the fixing device
according to the sixth embodiment.
BEST MODES FOR CARRYING OUT THE INVENTION
[0034] Next, a first embodiment of the present invention is
described with reference to FIGS. 1 to 6. In the first embodiment
described below, there is exemplified a fixing device 10 for
mounting a disk-shaped rotary blade 2 to a spindle 1 of a portable
circular saw. The spindle 1 of a circular sawing machine is rotated
about an axis J by a drive motor incorporated in a main body. At
the leading end of the spindle 1, a small diameter portion 1c is
formed in a stepped configuration to form an end portion Sa
perpendicular to the axis J. Flat surfaces 1a and 1a parallel with
each other are provided on the small diameter portion 1c, with the
axis J positioned therebetween. The two flat surfaces 1a and 1a
define a so-called two surface width portion S having an oval shape
in cross-section at the small diameter portion 1c of the spindle 1.
The two surface width portion S corresponds to an example of the
rotation fixing portion described in claims. Hereinafter, the two
surface width portion S is refereed to as a rotation fixing portion
S.
[0035] A threaded hole 1b is provided in the leading end surface of
the spindle 1 (leading end surface of the rotation fixing portion
S). The threaded hole 1b is provided along the central axis J of
the spindle 1 at a predetermined depth. The rotary blade 2 is
mounted to the rotation fixing portion S of the spindle 1 so as to
be immovable in the direction of the axis J and non-rotatable about
the axis J.
[0036] The fixing device 10 according to this embodiment includes
an inner flange 11 for contacting with one side surface of the
rotary blade 2 (left side surface in FIGS. 1 and 2), an
intermediate flange 12 for contacting with the other end surface of
the rotary blade 2 (right side surface in FIGS. 1 and 2), an outer
flange 13 for clamping the intermediate flange 12 between the outer
flange 13 and the rotary blade 2, and a fixing flange 14 for
clamping the outer flange 13 between the fixing flange 14 and the
intermediate flange 12.
[0037] The inner flange 11 has a disk shape, and an oval
through-hole 11a is provided at the center thereof. The rotation
fixing portion S is inserted into the through-hole 11a. Thus, the
inner flange 11 is mounted to the spindle 1 in a state of being
fixed with respect to the rotation. Further, the inner flange 11 is
mounted to the end portion Sa of the rotation fixing portion S in a
state of being in contact therewith while the displacement thereof
in the direction of the axis J (left hand in FIGS. 1 and 2) is
restricted.
[0038] An annular contact surface 11b is provided by thinning the
central portion of the side surface of the inner flange 11 on the
rotary blade 2 side (right side surface in the figure). The contact
surface 11b is brought to contact with the one side surface of the
rotary blade 2 (left side surface in the figure).
[0039] The inner flange 11 is mounted to the rotation fixing
portion S of the spindle 1, and then the rotary blade 2 is mounted
thereto. A circular attachment hole 2a is provided at the center of
the rotary blade 2. The rotation fixing portion S is inserted into
the attachment hole 2a, and the rotary blade 2 is attached to the
rotation fixing portion S of the spindle 1. Thus, the rotary blade
2 is mounted to the rotation fixing portion S while the rotation
thereof about the axis J is not directly fixed. Although the
illustration is omitted, a cutting edge is provided over the entire
periphery of the rotary blade 2.
[0040] The rotary blade 2 is mounted, and then the intermediate
flange 12 is mounted thereto. The intermediate flange 12 has a disk
shape of substantially the same outer diameter as that of the inner
flange 11, and an attachment hole 12a having a circular shape of
the same diameter as that of the rotary blade 2 is provided at the
center thereof. Thus, the intermediate flange 12 is also mounted to
the rotation fixing portion S while the rotation thereof about the
axis J is not directly fixed.
[0041] An annular contact surface 12b is provided by thinning the
central portion of the side surface of the intermediate flange 12
on the rotary blade 2 side (left side surface in the figure). The
contact surface 12b is brought to contact with the other side
surface of the rotary blade 2 (right side surface in the
figure).
[0042] In this context, the frictional resistance between the
contact surface 12b of the intermediate flange 12 and the rotary
blade 2 is set to be higher than the sliding resistance (frictional
resistance) between cam portions 12c and 13d described below. The
contact surface 12b of the intermediate flange 12 is treated with
so-called knurling (surface treatment for increasing frictional
resistance) so that the frictional resistance thereof against the
rotary blade 2 is set to be increased. Meanwhile, cam surfaces of
the cam portions 12c and 13d are formed to be flat and smooth so
that the sliding resistance therebetween is set to be sufficiently
lower than the frictional resistance of the intermediate flange 12
against the rotary blade 2.
[0043] Next, a plurality of cam portions 12c-12c are provided on
the right side surface of the intermediate flange 12. As
illustrated in FIG. 3, the cam portions 12c-12c include the
plurality (six in the figure) of cam portions 12c-12c provided
along the same circumference. As illustrated in FIG. 4, each of the
cam portions 12c has a triangular shape with its height
continuously varying in accordance with the direction of the axis
J.
[0044] A groove portion 12d is formed over the entire peripheral
surface of the intermediate flange 12. A retaining ring 15 is
fitted to the groove portion 12d.
[0045] The intermediate flange 12 is mounted, and then the outer
flange 13 is mounted to the rotation fixing portion S. The outer
flange 13 also has a substantially disk shape, and an oval
through-hole 13a is provided at the center thereof similarly to the
inner flange 11. The outer flange 13 is non-rotatably mounted to
the rotation fixing portion S of the spindle 1 while the rotation
fixing portion S is inserted into the through-hole 13a.
[0046] In FIGS. 1 and 2, an accommodating portion 13b for
accommodating the intermediate flange 12 is provided on the left
side surface of the outer flange 13. A groove portion 13c to which
the retaining ring 15 is fitted is formed on the entire periphery
of the inner wall surface of the accommodating portion 13b. By way
of the retaining ring 15, the outer flange 13 and the intermediate
flange 12 are assembled in a state of being rotatable relative to
each other and being not separable from each other in the direction
of the axis J.
[0047] Note that, the width of the groove portion 12d on the
intermediate flange 12 side is formed to be larger than that of the
groove portion 13c of the outer flange 13 side so that the
retaining ring 15 is displaceable in the direction of the axis J.
Thus, the intermediate flange 12 and the outer flange 13 are
assembled with each other so as to be relatively displaceable from
each other within a small range in the direction of the axis J
(range of relatively displacing in the direction of axis J due to
the sliding operation of cam portions 12c and 13c).
[0048] Next, on the bottom portion of the accommodating portion
13b, a plurality (six in this embodiment) of cam portions 13d to
13d are provided to oppose to the cam portions 12c to 12c of the
intermediate flange 12. The plurality of cam portions 13d to 13d
are provided along the circumference of substantially the same
diameter as that of the cam portions 12c to 12c on the intermediate
flange 12 side. Further, each of the cam portions 13d is formed so
as to be the same shape and size as that of each of the cam
portions 12c on the intermediate flange 12 side. Thus, the cam
portions 12c to 12c of the intermediate flange 12 and the cam
portions 13d to 13d of the outer flange 13 are in a state of being
meshed with each other. Mutual meshing between the cam portions 12c
to 12c and the cam portions 13d to 13d corresponds to the cam
meshing portion described in claims (hereinafter, the same
applies).
[0049] According to the cam meshing portion constituted as
described above by the intermediate flange 23 and the outer flange
13 paired with each other, when the outer flange 13 and the
intermediate flange 12 are rotated relatively to each other as
illustrated in FIG. 4, the meshing between the cam portions 13d to
13d and the cam portions 12c to 12c is shifted in the
circumferential direction so as to generate relative displacement
in the direction of the axis J, and hence the outer flange 13 and
the intermediate flange 12 are displaced relatively to each other
in the direction of the axis J. In the case of this embodiment, in
the state of being mounted to the spindle 1 as described later, the
outer flange 13 is fixed immovably in the direction of the axis J,
and therefore, when a relative rotational force with respect to the
intermediate flange 12 is applied to the outer flange 13, a part of
the rotational force acts as a large external force (axial force P)
in the direction of pressing the intermediate flange 12 against the
rotary blade 2 through the sliding operation between the cam
portions 12c and the cam portions 13d. The axial force P acts as a
clamping force for clamping the rotary blade 2 between the
intermediate flange 12 and the inner flange 11 whose axial movement
is restricted relative to the rotation fixing portion S.
[0050] In FIGS. 1 and 2, an accommodating portion 13e for
accommodating the fixing flange 14 is provided on the right side
surface of the outer flange 13. A groove portion 13f is similarly
formed on the entire periphery of the inner wall surface of the
accommodating portion 13e. A retaining ring 16 is fitted to the
groove portion 13f.
[0051] Further, an annular spring accommodating portion 13g is
provided at the bottom portion of the accommodating portion 13e. A
plate spring 17 for preventing backlash and loosening of the fixing
flange 14 is accommodated on the inner peripheral side of the
spring accommodating portion 13g. As illustrated in FIG. 5, in the
inner wall surface of the spring accommodating portion 13g, a large
number of semicircular engagement recessed portions 13h to 13h are
formed along the circumferential direction.
[0052] The fixing flange 14 has a substantially disk shape and a
fixing thread portion 14a provided at the center on the left side
surface thereof in FIGS. 1 and 2. The fixing thread portion 14a is
screwed into the threaded hole 1b provided in the end surface of
the spindle 1.
[0053] On the base portion of the fixing thread portion 14a, a
spring step portion 14b is provided in a stepped manner. The plate
spring 17 is arranged on the outer peripheral side of the spring
step portion 14b. The spring step portion 14b has substantially the
same vertical size as the thickness of the plate spring 17. As
illustrated in FIG. 5, at the circumferentially quadrisected
positions along an inner peripheral hole 17a of the plate spring
17, engagement protruding portions 17b to 17b are provided in a
state of radially protruding toward the center. Correspondingly,
engagement recessed portions 14c to 14c for fitting the engagement
protruding portions 17b without backlash are formed at the
peripheral quadrisected positions of the spring step portion 14b.
In a state in which the engagement protruding portions 17b are
fitted into the engagement recessed portions 14c without backlash,
the spring step portion 14b is inserted into the inner peripheral
hole 17a of the plate spring 17. Thus, the plate spring 17 is
mounted to the spring step portion 14b in a state of being
relatively non-rotatable about the axis J, and accordingly, is
integrally rotated with the fixing flange 14 by a rotational
manipulation of the fixing flange 14.
[0054] The plate spring 17 is provided with four engagement claw
portions 17c to 17c projecting in a curved manner from the
circumferentially quadrisected positions toward the outer
peripheral side thereof and extending in the same direction
substantially along the circumferential direction. Each of the
engagement claw portions 17c is resiliently biased toward the
radially outer peripheral side. As illustrated in FIG. 5, the
leading end portion of each of the engagement claw portions 17c is
formed so as to be a semicircular shape and are fitted by an
resilient force into each of the engagement recessed portions 13h
provided in the spring accommodating portion 13g of the outer
flange 13, and with this, the fixing flange 14 is prevented from
being loosened relative to the outer flange 13, and eventually, the
fixing thread portion 14a is prevented from being loosened relative
to the threaded hole 1b. It is possible to rotationally manipulate
the fixing flange 14 while displacing each of the engagement claw
portions 17c to the inner peripheral side against the resilient
force, whereby it is possible to tighten the fixing screw portion
14a into the threaded hole 1b of the spindle 1, and inversely, to
loosen the fixing screw portion 14a relative thereto.
[0055] A groove portion 14e is formed over the entire peripheral
surface of the fixing flange 14. The retaining ring 16 is fitted
into the groove portion 14e. By way of the retaining ring 16, the
fixing flange 14 is assembled with the outer flange 13 in a state
of being inseparable therefrom in the direction of the axis J and
relatively rotatable about the axis J. As a result, the fixing
flange 14, the outer flange 13, and the intermediate flange 12 are
assembled into one assembly. In this assembled state, the fixing
thread portion 14a of the fixing flange 14 is positioned coaxially
with respect to the axis J and positioned centrally of the
through-hole 13a of the outer flange 13 and the attachment hole 12a
of the intermediate flange 12. At this position, the fixing thread
portion 14a of the fixing flange 14 is tightened into the threaded
hole 1b of the spindle 1.
[0056] In FIGS. 1 and 2, a pinch portion 14d to be pinched by
finger tips of a user is provided at the center of the right side
surface of the fixing flange 14. As illustrated in FIG. 6, around
the pinch portion 14d, a slip-preventing portion 14f for preventing
slippage at the time of rotational manipulation is provided along
the annular range. The user can rotationally manipulate the fixing
flange 14 also by pressing the fingertips against the
slip-preventing portion 14f instead of the pinch portion 14. In
comparison with the case of rotationally manipulating the fixing
flange 14 by pinching the pinch portion 14, the rotational
manipulation can be performed more quickly in the case of
rotationally manipulating the fixing flange 14 by pressing the
fingertips against the slip-preventing portion 14f.
[0057] According to the fixing device 10 of the first embodiment
structured as described above, it is possible to firmly attach the
rotary blade 2 to the spindle 1 by a manual manipulation without
use of special tools, thereby enabling to reliably prevent slippage
of the rotary blade 2 relative to the inner flange 11, for example
during use of the rotary tool.
[0058] When attaching the rotary blade 2 to the rotation fixing
portion S of the spindle 1, the inner flange 11 of the fixing
device 10 is first mounted to the rotation fixing portion S. The
inner flange 11 is mounted relatively non-rotatably to the spindle
1 in a state in which the rotation fixing portion S is inserted
into the through-hole 11a thereof.
[0059] The inner flange 11 is mounted, and then the rotary blade 2
is mounted to the rotation fixing portion S. The rotation fixing
portion S is inserted into the attachment hole 2a of the rotary
blade 2, and the contact surface 11b of the inner flange 11 is
brought into contact with one side surface (left side surface in
FIG. 1) of the rotary blade 2. At this stage, the rotary blade 2 is
rotatable about the axis J relative to the spindle 1 and the
rotation fixing portion S thereof.
[0060] Next, the intermediate flange 12, the outer flange 13, and
the fixing flange 14 assembled to each other are mounted to the
rotation fixing portion S. In this case, the pinch portion 14d is
pinched with fingertips so as to rotationally manipulate the fixing
flange 14 in a tightening direction, whereby the fixing screw
portion 14a is tightened into the threaded hole 1b of the spindle
1. As the fixing screw portion 14a is tightened into the threaded
hole 1b, the rotation fixing portion S of the spindle 1 is inserted
into the attachment hole 12a of the intermediate flange 12, and
then into the through-hole 13a of the outer flange 13.
[0061] At an initial stage of tightening the fixing thread portion
14a, at which screw-tightening resistance is small, the fingertips
are pressed against the slip-preventing portion 14f of the fixing
flange 14 so as to rotationally manipulate the fixing flange 14,
whereby the rotational manipulation can be quickly performed.
[0062] During the rotational manipulation of the fixing flange 14,
the plate spring 17 is integrally rotated with the fixing flange
14. Thus, while each of the engagement claw portions 17c of the
plate spring 17 is engaged with and disengaged from the engagement
recessed portions 13h on the outer flange 13 side against an
resilient biasing force, the fixing flange 14 is rotated. The
rotational operability of the fixing flange 14 is enhanced owing to
clicking sound produced at the time the engagement claw portions
17c engage with and disengage from the engagement recessed portions
13h. The engagement claw portions 17c are fitted into the
engagement recessed portions 13h so as to be engaged therewith,
whereby the fixing flange 14, and eventually, the fixing thread
portion 14a is prevented from being loosened relative to the
threaded hole 1b.
[0063] When the fixing screw portion 14a is tightened into the
threaded hole 1b, the contact surface 12b of the intermediate
flange 12 is brought into contact with the other side surface of
the rotary blade 2 (right side surface in FIG. 1). Further, the cam
portions 12c to 12c on the intermediate flange 12 side and the cam
portions 13d to 13d on the outer flange 13 side come to mesh
completely with each other without being shifted in the
circumferential direction. As a result, both the flanges 12 and 13
become closest to each other in the direction of the axis J. FIG. 1
illustrates this state. As illustrated in the figure, the
intermediate flanges 12 and the outer flange 13 become closest to
each other in the direction of the axis J, and hence the retaining
ring 15 is positioned on the left side in the width direction of
the groove portion 12d of the intermediate flange 12.
[0064] In this manner, when the fixing flange 14 is rotated by
manual manipulation so that the fixing screw portion 14a thereof is
firmly tightened into the threaded hole 1b of the spindle 1,
attachment of the rotary blade 2 to the spindle 1 is completed.
[0065] In this attachment state, when the cutting resistance is
imparted to the rotary blade 2 or the inertia at the time of
braking or activation is produced therein so as to apply a force to
the rotary blade 2 in the direction of causing the rotary blade 2
to be rotated relatively to the spindle 1 (rotational resistance),
this rotational resistance acts as an external force in the
direction of pressing the intermediate flange 12 against the rotary
blade 2 because the frictional resistance of the contact surface
12b of the intermediate flange 12 against the rotary blade 2 is
larger than the sliding resistance between the cam portions 12c to
12c and the cam portions 13d to 13d, and the inner flange 11 and
the outer flange 13 are rotationally integrated with each other via
the rotation fixing portion S. That is, a rotational force for
relatively rotating the rotary blade 2 to the spindle 1 (external
force such as inertial force or cutting resistance) acts as an
external force in the direction of relatively displacing the cam
portions 12c to 12c and 13d to 13d in the circumferential
direction. Therefore, owing to the sliding operation between the
cam portions 12c and the cam portions 13d, a force component of the
rotational force in the direction of the axis J acts as the large
axial force P in the direction of pressing the intermediate flange
12 against the rotary blade 2. With this, the rotary blade 2 is
clamped between the inner flange 11 and the intermediate flange 12
with a large force, whereby the rotary blade 2 is prevented from
being slipped relative to the inner flange 11.
[0066] As described above, the fixing device 10 according to the
first embodiment has a function of converting the rotational
resistance imparted to the rotary blade 2 into a force for clamping
the rotary blade 2 between the inner flange 11 and the intermediate
flange 12 (clamping force). Thus, it is ensured that the rotary
blade 2 is prevented from slipping relative to the inner flange 11.
Further, the rotary blade 2 is firmly fixed with the axial force P
produced by the cam meshing portions, and hence it is only
necessary for a user to lightly tightening the fixing thread
portion 14a of the fixing flange 14 when attaching the rotary
blade. In this regard also, the fixing device 10 can be used more
conveniently.
[0067] In addition, the function of converting the rotational
resistance imparted to the rotary blade 2 into the clamping force
(axial force P) for the rotary blade 2 is structurally realized by
a slight displacement of the intermediate flange 12 relative to the
outer flange 13 in the direction of the axis J. Compactification in
the radial direction can be easily achieved in comparison with
conventional structures in which a ratchet mechanism for engaging
and disengaging meshing of teeth with recessed portions on the
outer peripheral side by displacing claw portions in the radial
direction, or in which a speed reduction gear train is arranged in
the radial direction. Thus, the illustrated fixing device 10 can be
applied to a portable circular saw without sacrificing the
inclination angle of the rotary blade, the cutting depth of the
rotary blade, and the like, at the time of performing oblique
cutting.
[0068] Further, the cam portions 12c of the intermediate flange 12
and the cam portions 13d of the outer flange 13 are formed to be a
triangular shape, and hence the rotational resistance in any
direction of the intermediate flange 12 relative to the outer
flange 13 (displacement in rotational direction) is also converted
into the axial force P in the direction of the axis J of the
intermediate flange 12 (pressing force against rotary blade 2).
Thus, according to the fixing device 10 in this embodiment, it is
possible to be functioned for rotational forces in any of the
directions caused by the cutting resistance imparted to the rotary
blade 2 during a cutting process and by the inertia at the time of
starting the rotation of the rotary blade 2 (activation) and at the
time of stopping the same (braking).
[0069] Various modifications can be made to the above-mentioned
first embodiment. For example, FIGS. 7 to 12 illustrate second to
sixth embodiments. In each of those embodiments, for parts and
structures similar to those in the first embodiment, the same
reference symbols are used, and the description thereof is omitted.
FIG. 7 illustrates a fixing device 20 according to the second
embodiment.
[0070] The fixing device 20 according to the second embodiment is
different from the first embodiment mainly in the structure of an
inner flange 21. The inner flange 21 according to the second
embodiment has a boss portion 21a provided at the center thereof.
The boss portion 21a protrudes toward the rotary blade 2 (right
side in FIG. 7). The boss portion 21a is inserted in the attachment
hole 2a of the rotary blade 2 in a state of being relatively
rotatable without backlash.
[0071] On the inner peripheral side of the boss portion 21a, there
is formed a through-hole 21b having a two surface width
sufficiently larger than the two surface width of the rotation
fixing portion S in size. Thus, the inner flange 21 is mounted to
the spindle 1 in a relatively rotatable state within a
predetermined angular range in a rotational direction thereof.
[0072] Between the inner flange 21 and the rotary blade 2, there is
clamped a disk-shaped slipping flange 22. As illustrated in the
figure, the boss portion 21a of the inner flange 21 is inserted
into the central hole of the slipping flange 22. Further, the
peripheral portion of the slipping flange 22 is folded back toward
the inner flange 21. A folded-back end portion 22a thus formed is
engaged with an engagement groove portion 21c provided in the
peripheral surface of the inner flange 21. Thus, the slipping
flange 22 is mounted in a state of covering substantially the
entire surface on the rotary blade 2 side of the inner flange 21
and in a state of being relatively rotatable about the axis J of
the spindle 1 and being not to be detach in the direction of the
axis J.
[0073] By way of the slipping flange 22, the frictional resistance
of the inner flange 21 in the rotational direction against the
rotary blade 2 is significantly reduced. The slipping flange 22
corresponds to an example of the friction reducing means described
in claims. Meanwhile, similarly to the first embodiment, an
intermediate flange 23 is in contact with the side surface on the
opposite side of the rotary blade 2 with large frictional
resistance.
[0074] The intermediate flange 23 is different from the
intermediate flange 12 according to the first embodiment in that a
central attachment hole 23a thereof is formed as a two surface
width hole. The attachment hole 23a of the intermediate flange 23
is formed to have the same diameter and the same dimension of the
two surface width as those of the through-hole 21b of the inner
flange 21. Thus, the intermediate flange 23 is mounted to the
rotation fixing portion S in a rotatable state within a
predetermined angular range. The relatively rotatable angle of the
intermediate flange 23 and the inner flange 21 to the rotation
fixing portion S is set to an angle corresponding to the relative
rotation of the cam meshing portion at which an axial force
sufficient for reliably fixing the rotary blade 2 can be produced.
Accordingly, the through-holes of the inner flange 21 and the
intermediate flange 23 may be formed not as two surface width holes
but as normal circular holes so as not to be restricted in the
rotational direction relative to the rotation fixing portion S.
[0075] Similarly to the first embodiment, the intermediate flange
23 is provided with the cam portions 12c to 12c, and the cam
portions 13d to 13d of the outer flange 13 mesh with the cam
portions 12c to 12c. The fixing thread portion 14a of the fixing
flange 14 is tightened into the threaded hole 1b of the spindle 1
so that the rotary blade 2 is clamped between the inner flange 21
and the intermediate flange 23. The cam portions 12c to 12c of the
intermediate flange 23 and the cam portions 13d to 13d of the outer
flange 13 mesh with each other with a tightening force (axial force
P) of the fixing thread portion 14a.
[0076] Similarly to the first embodiment, at the center of the
outer flange 13 paired with the intermediate flange 23 for
constituting the cam meshing portion, there is formed the
through-hole 13a having a two surface width (oval shape). The
rotation fixing portion S is inserted into the through-hole 13a
without a play in the rotational direction thereof. Thus, the outer
flange 13 is mounted to the rotation fixing portion S in a state of
being relatively non-rotatable.
[0077] In the fixing device 20 according to the second embodiment
structured as described above, when cutting resistance is imparted
to the rotary blade 2, the cutting resistance acts as a relative
rotational force between the intermediate flange 23 and the outer
flange 13. The relative rotational force acts as the axial force P
on the rotary blade 2 through the meshing operation between the cam
portions 12c and 13d, and the rotary blade 2 is firmly clamped
between the inner flange 21 and the intermediate flange 23 with the
axial force P. As a result, rotational torque of the spindle 1 is
efficiently transmitted to the rotary blade 2.
[0078] When the spindle 1 stops and cutting resistance (rotational
resistance) is not imparted to the rotary blade 2, the meshing
between the cams 12c and 13d is loosened. As a result, a clamping
force of the inner flange 21 and the intermediate flange 23 against
the rotary blade 2 is lowered, and a tightening force of the fixing
thread portion 14a, which acts on the flanges 21, 23, and 13, is
reduced. Thus, it is possible to easily rotate the fixing flange 14
with a small force in the loosening direction.
[0079] Especially, in the case of the second embodiment, the
slipping flange 22 is clamped between the inner flange 21 and the
rotary blade 2. Thus, at the time no cutting resistance is imparted
to the rotary blade 2, the rotation of the rotary blade 2 and the
intermediate flange 23 more easily occurs relative to the inner
flange 21, and eventually, the rotation fixing portion S.
Accordingly, the cam portions 12c and 13d are more easily loosened,
whereby the tightening force of the fixing thread portion 14a is
more reliably reduced. As a result, it is possible to rotationally
manipulate the fixing flange 14 in the loosening direction further
easily.
[0080] Further, in the second embodiment, the inner flange 21 is
mounted to the rotation fixing portion S of the spindle 1 in a
rotatable state within a predetermined angular range. In this
regard also, the cam portions 12c and 13d are more easily loosened
in comparison with the first embodiment, and eventually, the fixing
flange 14 is more easily rotated in the loosening direction with a
smaller force.
[0081] Next, FIG. 8 illustrates a fixing device 30 according to the
third embodiment, in which a further modification is added to the
second embodiment. The fixing device 30 according to the third
embodiment is different from the fixing device 20 according to the
second embodiment in that a cover 35 made of elastic rubber is
mounted around an intermediate flange 31, an outer flange 32, and a
fixing flange 33. For, the parts and structures similar to those in
the first and second embodiment, the same reference symbols are
used, and the description thereof is omitted.
[0082] In the first and second embodiments, the retaining ring 15
restricts the displacement (detachment) of the outer flange 13
relative to the intermediate flange 23 in the direction of the axis
J, and the retaining ring 16 restricts the displacement
(detachment) of the fixing flange 14 relative to the outer flange
13 in the direction of the axis J. In the fixing device 30
according to the third embodiment, the cover 35 restricts these
displacements. The entire peripheral surfaces of the intermediate
flange 31, the outer flange 32, and the fixing flange 33 are
respectively provided with engagement groove portions 31a, 32a, and
33a. Correspondingly, the cover 35 has a substantially conical
tubular shape having a diameter reducing toward the fixing flange
33, and three engagement protruding portions 35a, 35b, and 35c are
respectively formed correspondingly to the engagement groove
portions 31a, 32a, and 33a on the entire inner peripheral surface
thereof. The engagement protruding portion 35a on the largest
diameter side is fitted along the engagement groove portion 31a of
the intermediate flange 31, the engagement protruding portion 35c
on the smallest diameter side is fitted along the engagement groove
portion 33a of the fixing flange 33, and the engagement protruding
portion 35b provided therebetween is fitted along the engagement
groove portion 32a of the outer flange 32. Each of the widths of
the engagement protruding portions 35a, 35b, and 35c, and each of
the widths of the engagement groove portions 31a, 32a, and 33a are
dimensioned for allowing the engagement protruding portions 35a,
35b, and 35c to be elastically deformed in the width directions
thereof and pressed into the engagement groove portions 31a, 32a,
and 33a, respectively. Thus, the relative rotation between the
intermediate flange 31, the outer flange 32, and the fixing flange
33 is performed by elastic deformation of the cover 35 in the
rotational direction. In a state in which no external force in the
rotational direction is imparted to each of the flanges 31, 32, and
33, the flanges 31, 32, and 33 are mutually maintained in a
predetermined positional relation by the cover 35. In this
embodiment, the predetermined position is set to be a position
(initial position) at which the cam portions 12c of the
intermediate flange 31 and the cam portions 13d of the outer flange
32 mesh most deeply with each other.
[0083] Similarly to the first and second embodiments, the cam
portions 12c to 12c of the intermediate flange 31 and the cam
portions 13d to 13d of the outer flange 32 mesh with each other.
The engagement between both the cam portions 12c and 13d is biased
toward the initial position where they mesh most deeply with each
other (position at which intermediate flange 31 and outer flange 32
are brought to be closest to each other in the direction of axis J)
by an elastic force in the rotational direction of the cover 35.
Further, also in the third embodiment, at the center of the
intermediate flange 31, there is provided a through-hole 31b of a
hole shape having a two surface width similar to the intermediate
flange 23 according to the second embodiment. The rotation fixing
portion S of the spindle 1 is passed through the through-hole 31b.
Thus, the intermediate flange 31 is mounted in a rotatable state
within a predetermined angular range in a rotational direction
thereof similarly to the inner flange 21.
[0084] In the fixing device 30 according to the third embodiment
structured as described above, by an elastic force in the
rotational direction of the cover 35, the cam portions 12c of the
intermediate flange 31 and the cam portions 13d of the outer flange
32 are biased in the direction of meshing most deeply with each
other. Thus, when the cutting resistance is no longer applied to
the rotary blade 2, the engagement between the cam portions 12c and
13d is instantly and reliably transferred to an initial state, in
which the engagement becomes most deeply by the elastic force of
the cover 35. As a result, the clamping force of the inner flange
21 and the intermediate flange 31 against the rotary blade 2 is
released, and the tightening force of the fixing thread portion 14a
is reduced. Thus, it is possible to rotationally manipulate the
fixing flange 35 more reliably with a small force in the loosening
direction.
[0085] Further, in the fixing device 30 according to the third
embodiment, the cover 35 covers the periphery around between the
intermediate flange 31, the outer flange 32, and the fixing flange
33. Therefore, intrusion of foreign matters into between the
flanges 31, 32, and 33 is prevented in advance.
[0086] Although the illustration is omitted, the following
modifications can be made to the third embodiment described above.
In the third embodiment, there is illustrated a structure in which
the intermediate flange 31, the outer flange 32, and the fixing
flange 33 are engaged with each other in the rotational direction
by means of the single cover 35, and the cover 35 covers the
periphery thereof. However, separate covers may elastically bias in
the rotational direction between the intermediate flange 31 and the
outer flange 32 and between the outer flange 32 and the fixing
flange 33 and may cover the peripheries thereof.
[0087] Further, not by means of the cover 35 made of elastic
rubber, the flanges 31, 32, and 33 may be resiliently biased in the
rotational direction to each other by, for example, torsion coil
springs interposed therebetween. Even in the structure in which the
torsion coil springs are used as an initial position biasing means,
the cam portions 12c and 13d can be biased in the direction of
meshing most deeply with each other, and hence the same operations
and effects as those described above can be obtained, although the
foreign matter intrusion preventing function may be lowered.
Accordingly, the cover may be omitted between the outer flange 32
and the fixing flange 33.
[0088] Next, FIG. 9 illustrates a fixing device 40 according to the
fourth embodiment. The fixing device 40 according to the fourth
embodiment is different from the fixing device 20 of the second
embodiment in that the positions of the cam meshing portion (cam
portions 12c to 12c and 13d to 13d) and the slipping flange 22 are
changed to be reversed with respect to the rotary blade 2. The
fixing device 40 according to the fourth embodiment corresponds to
the embodiment of the invention described in claim 8. For arts and
structures similar to those in the second embodiment the same
reference symbols are used, and the description thereof is
omitted.
[0089] In the case of the fourth embodiment, an inner flange 41 and
an intermediate flange 42 are arranged on the left side in the
figure relative to the rotary blade 2 (base portion side of spindle
1), and an outer flange 43 and the fixing flange 14 are arrange on
the right side in the figure (leading end side of the spindle
1).
[0090] Cam portions 41a to 41a are provided on the side surface on
the rotary blade 2 side of the inner flange 41, and cam portions
42a to 42a are provided on the side surface opposite to the rotary
blade 2 side of the intermediate flange 42. Both the cam portions
41a to 41a and 42a to 42a are in mesh with each other.
[0091] A through-hole 41b having a two surface width is provided at
the center of the inner flange 41. The rotation fixing portion S of
the spindle 1 is inserted into the through-hole 41b. In the case of
the fourth embodiment, the inner flange 41 is non-rotatably mounted
to the spindle 1. As is already apparent from the above, the
flanges on the side of being paired with the intermediate flanges
for constituting the cam meshing portions (outer flanges 13 and 32
in the first to third embodiments and inner flange 41 in the fourth
embodiment) are non-rotatably mounted to the rotation fixing
portion S.
[0092] At the center of the intermediate flange 42, there is
provided a boss portion 42b. The boss portion 42b is inserted in
the attachment hole 2a of the rotary blade 2 without backlash in
the radial direction, whereby the rotary blade 2 is held in contact
with the side surface of the intermediate flange 42. On the inner
peripheral side of the boss portion 42b, there is provided a
through-hole 42c having a two surface width correspondingly to the
rotation fixing portion S of the spindle 1. Note that, similarly to
the through-hole 21b of the inner flange 21 in the second
embodiment, the through-hole 42c is dimensioned for allowing the
intermediate flange 42 to rotate relative to the rotation fixing
portion S of the spindle 1 within a predetermined angular
range.
[0093] By way of a retaining ring 44, the inner flange 41 and the
intermediate flange 42 are allowed to be relatively rotated about
the axis J, while the displacement in the direction of the axis J
is restricted within a predetermined range, whereby the detachment
thereof is prevented.
[0094] Similarly to the slipping flange 22 of the second
embodiment, the outer flange 43 is in contact with the rotary blade
2 while a slipping flange 45 made of a material having small
frictional resistance is clamped between the outer flange 43 and
the rotary blade 2. The slipping flange 45 also corresponds to an
example of the friction reducing means described in claims.
[0095] At the center of the slipping flange 45, there is provided a
through-hole 45b having a circular shape of the same diameter as
that of the attachment hole 2a of the rotary blade 2. The rotation
fixing portion S of the spindle 1 is passed through the
through-hole 45b. The outer peripheral side of the slipping flange
45 is folded back similarly to the second embodiment, and a
folded-back portion 45a thus formed is inserted into an engagement
groove 43b provided over the entire outer peripheral surface of the
outer flange 43. Thus, the slipping flange 45 is mounted not to be
displaceable in the direction of the axis J and to be relatively
rotatable about the axis J in a state of covering substantially the
entire side surface of the outer flange 43.
[0096] Also, on the inner peripheral side of the outer flange 43,
there is provided a through-hole 43a having a two surface width.
The rotation fixing portion S of the spindle 1 is passed through
the through-hole 43a. Similarly to the through-hole 42c of the
intermediate flange 42, the through-hole 43a is dimensioned to have
a two surface width for allowing the outer flange 43 to be rotated
within a predetermined range in the rotational direction relative
to the rotation fixing portion S. By way of the retaining ring 16,
the outer flange 43 and the fixing flange 14 are assembled such
that they are allowed to be rotated relatively about the axis J,
while their displacement in the direction of the axis J is
restricted to prevent detachment from each other.
[0097] By the fixing device 40 according to the fourth embodiment
structured as described above, the same operations and effects as
those in the above-mentioned embodiments can also be obtained. When
a user lightly tightens the fixing flange 14, the rotary blade 2 is
clamped between the intermediate flange 42 and the outer flange 43
owing to a tightening force of the fixing thread portion 14a. When
cutting resistance is imparted to the rotary blade 2, the meshing
between the cam portions 41a and 42a becomes shallower, and a
clamping force of the intermediate flange 42 and the outer flange
43 is increased. Thus, the rotary blade 2 is firmly fixed to the
rotation fixing portion S in a state of being non-rotatable and
immovable in the axial direction. When no cutting resistance is no
longer imparted to the rotary blade 2, the meshing between the cam
portions 41a and 42a becomes deeper so that the cam meshing portion
is restored to the initial position. Thus, the clamping force of
the intermediate flange 42 and the outer flange 43 is reduced,
whereby the tightening force of the fixing thread portion 14a is
weakened so that it is possible to rotationally manipulate the
fixing flange 14 in a loosening direction with a small force.
Further, the slipping flange 45 is clamped on the side of the outer
flange 43, and the outer flange 43 is mounted to the rotation
fixing portion S in a rotatable state within a predetermined
angular range. Thus, the relative rotation between the rotary blade
2 and the intermediate flange 42 more easily occurs relative to the
outer flange 43, and eventually, relative to the rotation fixing
portion S. As a result, it is possible to displace the intermediate
flange 42 in the direction in which the cam portions 41a and 42a
mesh more deeply with each other, to thereby more reliably reduce
the tightening force of the fixing thread portion 14a.
[0098] Next, FIG. 10 illustrates a fixing device 50 according to
the fifth embodiment, which is a combination of the second
embodiment and the fourth embodiment. The fixing device 50
according to the fifth embodiment is different from the first to
fourth embodiments in that the cam meshing portions are provided on
both sides with respect to the rotary blade 2. That is, while one
set of the cam portions is provided in the first to fourth
embodiments, two sets of cam portions are provided in the fifth
embodiment. The fixing device 50 according to the fifth embodiment
corresponds to the embodiment of the invention described in claim
9. For parts and structures similar to those in the first to fourth
embodiments, the same reference symbols are used, and the
description thereof is omitted.
[0099] The fixing device 50 includes an inner flange 51, an inner
intermediate flange 52, an outer intermediate flange 53, an outer
flange 54 and the fixing flange 14 in the order from the left side
in FIG. 10. On the left side in the figure with respect to the
rotary blade 2, a combination of the inner flange 41 and the
intermediate flange 42 in the fourth embodiment is used, and on the
right side in the figure with respect to the rotary blade 2, a
combination of the intermediate flange 23 and the outer flange 13
in the second embodiment is used. Note that, the slipping flange 22
is not used in the case of the fifth embodiment.
[0100] Cam portions 51a of the inner flange 51 and cam portions 52a
of the inner intermediate flange 52 mesh with each other, and cam
portions 53a of the outer intermediate flange 53 and cam portions
54a of the outer flange 54 mesh with each other. At the respective
centers of the inner flange 51 and the outer flange 54, there are
provided through-holes 51b and 54b each having a two surface width,
and the rotation fixing portion S of the spindle 1 is passed on
their inner peripheral sides in a state of being relatively
non-rotatable. At the respective centers of both the intermediate
flanges 52 and 53, there are provided through-holes 52b and 53b
each having a two surface width. Note that, each of the two surface
widths of both the through-holes 52b and 53b is dimensioned for
allowing relative rotation of both the intermediate flanges 52 and
53 within a predetermined angular range in the rotational direction
relative to the rotation fixing portion S of the spindle 1. A boss
portion 52c is provided at the center of the inner intermediate
flange 52. The through-hole 52b is provided on the inner peripheral
side of the boss portion 52c. The boss portion 52c is inserted into
the attachment hole 2a of the rotary blade 2 without backlash in
the radial direction.
[0101] By way of the retaining ring 44, the inner flange 51 and the
inner intermediate flange 52 are combined with each other without
backlash in the direction of the axis J while being relatively
rotatable about the axis J. Further, by way of the retaining ring
15, the outer intermediate flange 53 and the outer flange 54 are
combined with each other, and by way of the retaining ring 16, the
outer flange 54 and the fixing flange 14 are combined with each
other, in either case, without backlash in the direction of the
axis J while being relatively rotatable about the axis J.
[0102] In the fixing device 50 according to the fifth embodiment,
which is provided with two sets of the cam meshing portions, when
the cutting resistance is no longer imparted to the rotary blade 2,
relative rotational forces are no longer imparted between the inner
flange 51 and the inner intermediate flange 52 and between the
outer intermediate flange 53 and the outer flange 54. As a result,
the meshing of the cam portions on both the sides of the rotary
blade 2 becomes most deeply so that the tightening force of the
fixing thread portion 14a is instantly weakened. Accordingly, it is
possible to rotationally manipulate the fixing flange 14 in a
loosening direction with a small force.
[0103] Especially, in the case of the fifth embodiment, two sets of
the cam portions are provided on both sides of the rotary blade 2.
Thus, when the rotational resistance is no longer imparted to the
rotary blade 2 and consequently rotational forces are no longer
imparted to both the intermediate flanges 52 and 53, the deepest
meshing with the cam portions 51a and 54a occurs, respectively. As
a result, it is possible to obtain a displacement amount of both
the intermediate flanges 52 and 53 in the direction of the axis J,
which is approximately twice as large as that in the case of the
second or fourth embodiment, thereby enabling to more reliably and
quickly loosen the fixing screw portion 14a.
[0104] Further, by the axial force P produced by two sets of the
cam portions, the rotary blade 2 is firmly fixed. Therefore, it is
only necessary for a user to lightly tighten the fixing flange 14
at the time of mounting the blade. In this regard, similarly to the
above-mentioned embodiments, the fixing device 50 can be used more
conveniently.
[0105] Next, FIGS. 11 and 12 illustrate a fixing device 60
according to the sixth embodiment. The fixing device 60 is
constructed to interpose two plate springs 61 and 62 between the
intermediate flange 23 and the outer flange 13 in the fixing device
20 according to the second embodiment. For parts and structures
similar to those in the second embodiment, the same reference
symbols are used, and the description thereof is omitted.
[0106] In the case of the sixth embodiment, at the center of an
intermediate flange 63, there is provided a through-hole 63a formed
to have a two surface width for allowing the intermediate flange 63
to be rotated within a predetermined angular range in the
rotational direction relative to the rotation fixing portion S of
the spindle 1. The rotation fixing portion S of the spindle 1 is
passed through the through-hole 63a. As illustrated in FIG. 12, in
two areas on the periphery of the through-hole 63a, there are
provided semicircular spring accommodating portions 63b and 63c.
Both the spring accommodating portions 63b and 63c are formed in
the side surface on the fixing flange 14 side to have small depths
in the thickness direction of the intermediate flange 63 (direction
of axis J). The plate springs 61 and 62 are accommodated in the
spring accommodating portions 63b and 63c, respectively.
[0107] Both the plate springs 61 and 62 are small pieces having
band plate shapes and are bent at both end portions thereof.
Respective bent end portions 61a, 61a, 62a, and 62a of the plate
springs 61 and 62 are resiliently engaged with larger diameter side
surfaces of the spring accommodating portions 63b and 63c, and are
retained in such a state that both the plate springs 61 and 62 are
shored. Thus, both the plate springs 61 and 62 are fixed so as not
to shift about the axis J or in the radial direction. Both centers
with respect to the longitudinal directions of the plate springs 61
and 62 are in contact with flat surfaces 1a of the rotation fixing
portion S of the spindle 1, respectively. The interval between both
the plate springs 61 and 62 substantially corresponds to the
surface width between the two flat surfaces 1a and 1a of the
spindle 1. With biasing forces of both the plate springs 61 and 62,
an intermediate flange 63 is biased to be restored to a
predetermined position (position at which both plate springs 61 and
62 are in contact with the flat surfaces 1a of the rotation fixing
portion S of spindle 1, that is, a position illustrated in FIG. 12,
hereinafter refereed to as initial position) about the axis J of
the spindle 1 (in a rotational direction).
[0108] In addition, the positional relation between both the plate
springs 61 and 62 and the flat surface 1a of the rotation fixing
portion S is properly set such that cam portions 63d to 63d of the
intermediate flange 63 and cam portions 64a to 64a of an outer
flange 64 mesh most deeply with each other in a state in which the
intermediate flange 63 is restored to the initial position with the
biasing forces of both the plate springs 61 and 62. The outer
flange 64 has a through-hole 64b provided at the center thereof and
formed as a hole having a two surface width, and hence is mounted
to the rotation fixing portion S in a state of being fixed with
respect to the rotation.
[0109] In the fixing device 60 according to the sixth embodiment
structured as described above, the intermediate flange 63 is biased
by the plate springs 61 and 62 to the initial position at which the
cam portions 63d and 64a mesh most deeply with each other. Thus,
when the rotational resistance is no longer imparted to the rotary
blade 2 and the intermediate flange 63, the intermediate flange 63
is reliably and instantly restored to the initial position by the
biasing forces of both the plate springs 61 and 62. As a result,
the cam portions 63d of the intermediate flange 63 and the cam
portions 64a of the outer flange 64 mesh most deeply with each
other, and the clamping force of the inner flange 21 and the
intermediate flange 63 against the rotary blade 2 is instantly
released. With this, the tightening force of the fixing thread
portion 14a against the threaded hole 1b is weakened, and hence, in
the case of replacing the rotary blade 2 and the like, the fixing
flange 14 can be easily rotated with a small force in the loosening
direction.
[0110] When the spindle 1 is rotated again so as to perform a
cutting process, rotational resistance is imparted to the rotary
blade 2. As a result, the intermediate flange 63 is displaced from
the initial position against the biasing forces of both the plate
springs 61 and 62, and the cam portions 63d thereof and the cam
portions 64a of the outer flange 64 are displaced relative to each
other. With this, the clamping force of the intermediate flange 63
and the inner flange 21 is instantly increased, whereby a state is
achieved in which the rotary blade 2 is firmly fixed to the spindle
1 in the rotational direction and in the direction of the axis
J.
[0111] Further, similarly to the second embodiment, the slipping
flange 22 is clamped between the inner flange 21 and the rotary
blade 2, and the inner flange 21 is mounted to the rotation fixing
portion S of the spindle 1 with a suitable play in the rotational
direction. Thus, when rotational resistance is no longer imparted
after completion of the cutting process, the rotation of the rotary
blade 2 and the intermediate flange 63 relative to the inner flange
21 is caused more easily. In this regard also, the rotational
manipulation in the loosening direction of the fixing flange 14 can
be more easily performed.
[0112] Other various modifications can be made to the embodiments
described above. For example, in the first embodiment, there is
illustrated the structure in which so-called knurling is applied on
the contact surface 12b of the intermediate flange 12, whereby
frictional resistance of the contact surface 12b of the
intermediate flange 12 against the rotary blade 2 is set to be
larger than frictional resistance between the cam portions 12c to
12 and 13d to 13d. In this context, it may be possible to construct
such that materials contacting or sliding contacting with each
other are properly set, whereby the frictional resistance of the
intermediate flange 12 against the rotary blade 2 is set to be
larger than the frictional resistance between the cam portions 12c
to 12c and the cam portions 13d to 13d.
[0113] Further, in the illustrated embodiments, it may be possible
to construct such that liners with high slide ability are attached
to the cam portions 12c to 12 and the cam portions 13d to 13d or a
lubricant is applied thereto so as to lower sliding resistance
thereof, and a slip-preventing member is attached to the contact
surface 12b of the intermediate flange 12 so that a suitable
difference is obtained between the sliding resistance between the
cam portions 12c and 13d and the frictional resistance of the
intermediate flange 12 against the rotary blade 2.
[0114] Further, the contact area of the contact surface 12a of the
intermediate flange 12 with the rotary blade 2 may be increased,
whereby the frictional resistance thereof can be set to be larger
than the sliding resistance between the cam portions 12c and 13d.
With this, the same operations and effects as described above can
be obtained.
[0115] In addition, the contact surface 12b of the intermediate
flange 12 with the rotary blade 2 is positioned on the outer
peripheral side of the sliding-contact portion between the cam
portions 12c and 13d, and hence large frictional resistance can be
easily obtained for the former.
[0116] Further, in the embodiments, there is illustrated the
structure in which the threaded hole 1b is provided at the leading
end of the spindle 1 and the fixing thread portion 14a is provided
to the fixing flange 14. On the contrary, it may be possible to
construct such that a threaded shaft portion is provided on the
spindle 1 side and a female thread portion (nut portion) is
provided on the fixing flange 14 side, so that they are threadably
coupled to each others.
[0117] Further, in the second, third, and sixth embodiments, there
is illustrated the structure in which the slipping flange 22 is
used as the friction reducing means for reducing the frictional
resistance in the rotational direction of the inner flange 21
against the rotary blade 2 in comparison with the frictional
resistance in the rotational directions of the intermediate flanges
23, 31, and 63 against the rotary blade 2. In this context, it may
be possible to construct such that, as the friction reducing means,
a lubricant such as molybdenum grease is further applied onto one
or both of the surfaces of the slipping flange 22, or a surface
layer with high slide ability is coated by plating or the like on
one or both of the inner flange 21 and the rotary blade 2, whereby
the frictional resistance in the rotational direction of the inner
flange 21 against the rotary blade 2 is reduced.
[0118] Further, it is possible to construct such that, as a
friction reducing means, a thrust bearing is interposed in place of
the slipping flange 22, whereby friction in the rotational
direction of the inner flange against the rotary blade is reduced.
In addition, in place of the slipping flange 22 as a friction
reducing means, the flanges on the side of not constituting the cam
meshing portions by being paired with the intermediate flanges
(inner flange 21 according to the second and third embodiments,
outer flange 43 according to the fourth embodiment, and inner
flange 21 according to the sixth embodiment) can be constructed to
be relatively rotatable to the rotation fixing portion S at least
within a predetermined angular range, whereby a relative
displacement in the cam meshing portion can be further facilitated.
The rotation within a predetermined angular range can be obtained
not only in the structure in which the though-hole allowing the
rotation fixing portion S to pass therethrough is formed as a
circular hole, but also by loosening the restriction in the
rotational direction (enlarging a two surface width) even in the
case of a through-hole having a two surface width.
[0119] In addition, as a structure common to the illustrated
embodiments, the following basic structure can be led. First, the
intermediate flange is not fixed to the rotation fixing portion S
with respect to the rotation. Second, the flange paired with the
intermediate flange for constituting the cam meshing portion is
fixed to the rotation fixing portion S with respect to the
rotation. Third, the flange which does not constitute the cam
meshing portion by being paired with the intermediate flange is not
fixed to the rotation fixing portion S with respect to the
rotation. Fourth, even when the flange which does not constitute
the cam meshing portion by being paired with the intermediate
flange is similarly fixed to the rotation fixing portion S with
respect to the rotation, the friction reducing means is interposed
between the flange and the rotary blade, whereby the relative
rotation of the rotary blade relative to the rotation fixing
portion S is facilitated by the relative rotation therebetween. As
a result, the same function as that of the third structure can be
obtained.
[0120] In the third structure, in is possible to incorporate a
structure in which the through-hole is formed as a circular hole,
and consequently there is no restriction in the rotational
direction unless the rotation is fixed by the rotation fixing
portion S, or a structure in which, the through-hole is formed as a
hole having a two surface width but the two surface width is loose
enough in comparison with the two surface width dimension of the
rotation fixing portion S, and consequently there is a play within
a predetermined range in the rotational direction. With any of the
third and fourth structures, it is possible to produce the axial
force P sufficient for firmly clamping the rotary blade by the
relative rotation of the cam portions meshing with each other in
the cam meshing portion at a predetermined angle, and inversely,
possible to release the axial force P.
[0121] Further, while the two surface width portion S is
illustrated as a rotation fixing portion, alternatively, a shaft
portion rectangular in cross-section or hexagonal in cross-section
may be incorporated as the rotation fixing portion.
[0122] In addition, although the illustration is omitted, in the
fourth and fifth embodiments, it is possible to construct such that
the initial position biasing means as illustrated in the third and
sixth embodiments are used, whereby the cam meshing portion is
biased in the direction in which the meshing of the cam meshing
portions becomes most deeply.
[0123] Further, in the sixth embodiment, there is illustrated the
structure in which, regarding the position in the rotational
direction of the intermediate flange 63 relative to the rotation
fixing portion S, the two plate springs 61 and 62 are used as the
initial position biasing means for biasing toward the initial
position at which the cam portions 63d to 63d of the intermediate
flange 63 and the cam portions 64a to 64a of the outer flange 64
most deeply mesh with each other. However, alternatively, it is
possible to construct such that coil springs such as compression
springs, tension springs, or torsion springs or other biasing means
are used.
[0124] Further, although there is illustrated the case where the
rotary blade 2 is fixed to the spindle 1 of a portable circular
saw, the fixing device according to the present invention may be
similarly applied in the case of attaching the rotary blade to
spindles of other rotary tools such as a bench type or installation
type circular sawing machine, a grinder, or a polishing
instrument.
* * * * *