U.S. patent application number 11/495777 was filed with the patent office on 2006-11-23 for portable circular power saw with optical alignment.
This patent application is currently assigned to HITACHI KOKI CO., LTD.. Invention is credited to Naoya Etou, Akira Onose, Shinji Takano.
Application Number | 20060265206 11/495777 |
Document ID | / |
Family ID | 27347459 |
Filed Date | 2006-11-23 |
United States Patent
Application |
20060265206 |
Kind Code |
A1 |
Onose; Akira ; et
al. |
November 23, 2006 |
Portable circular power saw with optical alignment
Abstract
A laser emitter projects a planer light beam to form an optical
guideline on a work piece extending in a cutting direction of saw
blade. The laser emitter is arranged behind, in the cutting
direction, a tangential line of the circumference of the saw blade
at an intersection of a bottom surface of the base and the
circumference at a front side of the base in the cutting direction.
The laser emitter forms the optical guideline behind the
intersection in the cutting direction. The laser emitter is
supported in respect of the saw blade slidingly in a direction
defined by a rotation axis of the saw blade. The saw cover may have
a window to transmit the laser beam toward the cutting point. A
shutter selectively shutting the window may be provided.
Inventors: |
Onose; Akira;
(Hitachinaka-shi, JP) ; Etou; Naoya;
(Hitachinaka-shi, JP) ; Takano; Shinji;
(Hitachinaka-shi, JP) |
Correspondence
Address: |
MCDERMOTT WILL & EMERY LLP
600 13TH STREET, N.W.
WASHINGTON
DC
20005-3096
US
|
Assignee: |
HITACHI KOKI CO., LTD.
Tokyo
JP
|
Family ID: |
27347459 |
Appl. No.: |
11/495777 |
Filed: |
July 31, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10227418 |
Aug 26, 2002 |
7096587 |
|
|
11495777 |
Jul 31, 2006 |
|
|
|
Current U.S.
Class: |
704/1 |
Current CPC
Class: |
Y10T 83/768 20150401;
B23D 59/003 20130101; B25H 1/0092 20130101; Y10T 83/828
20150401 |
Class at
Publication: |
704/001 |
International
Class: |
G06F 17/20 20060101
G06F017/20 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 7, 2001 |
JP |
2001-272420 |
Sep 7, 2001 |
JP |
2001-272421 |
Feb 20, 2002 |
JP |
2002-43517 |
Claims
1. A cutting tool, comprising: a housing; a motor which is
supported by the housing and rotates a detachable saw blade to cut
a work piece; a saw cover which is supported by the housing and has
a shape so as to cover a portion of the saw blade; a fixing member
which is fixed to the saw cover; a laser emitter which emits a
planer light beam to form an optical guide line on an upper surface
of the work piece; and an adjustment mechanism which is disposed
between the fixing member and the laser emitter and causes the
laser emitter to be movable in parallel to a rotation axis of the
saw blade, wherein the adjustment mechanism comprises: a sliding
member which supports the laser emitter; a pin which guides the
sliding member to be moved; a bolt which penetrates through a
through hole of the fixing member and is engaged with a screw hole
of the sliding member; and a spring which is placed between the
fixing member and the sliding member and biases the sliding member,
and wherein the laser emitter is moved in parallel to the rotation
axis of the saw blade when the bolt is rotated.
2. The tool according to claim 1, wherein the spring is formed of a
coil spring, and the bolt is covered with the spring.
3. A laser assembly for a cutting tool, comprising: A fixing member
which is fixed to a cutting tool having a rotatable saw blade; A
laser emitter which emits a planer light beam to form an optical
guide line on an upper surface of a work piece; and an adjustment
mechanism which is disposed between the fixing member and the laser
emitter and causes the laser emitter to be movable in parallel to a
rotation axis of the saw blade, wherein the adjustment mechanism
comprises: a sliding member which supports the laser emitter; a pin
which guides the sliding member to be moved; a bolt which
penetrates through a through hole of the fixing member and is
engaged with a screw hole of the sliding member; and a spring which
is placed between the fixing member and the sliding member and
biases the sliding member, and wherein the laser emitter is moved
in parallel to the rotation axis of the saw blade when the bolt is
rotated.
4. The assembly according to claim 3, wherein the spring is formed
of a coil spring, and the bolt is covered with the spring.
5-17. (canceled)
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] This invention relates to a portable circular power saw with
optical alignment.
[0003] 2. Description of the Prior Art
[0004] When an operator cuts a work piece with a portable circular
power saw, the operator draws a cutting line on the work piece and
then cuts the work piece with aligning either side surface of the
saw blade (edges) with the cutting line.
[0005] FIGS. 11 and 12 show a prior art portable circular power
saw. When cutting a work piece 316 with this prior art power saw,
the operator aligns an edge of a guide piece 312 with the cutting
line 15 on the work piece 316 as shown in FIG. 12. Next, the
operator rotates the saw blade 301 and pushes the housing forwardly
(in the cutting direction) with keeping this alignment
condition.
[0006] DE3922849 discloses a prior art power saw with optical
alignment, wherein the optical guideline is generated on a work
piece by a laser emitter. However, the optical guideline is only
generated beyond the edge of the base. In other words, this prior
art power saw cannot form the optical guideline near the saw blade.
The optical guideline system in the power saw requires initial
alignment between the saw blade and the optical guideline because
the operator selects either of side surfaces of saw blade to be
aligned with the cutting line on the work piece. However, in this
prior art power saw, it is difficult to conduct the initial
alignment between the saw blade and the optical guideline and
impossible to align the cutting line with the optical guideline
near the saw blade.
[0007] U.S. Pat. No. 5,375,495 discloses a portable circular power
saw with optical alignment system capable of aligning the optical
guideline with the saw blade and with a cutting line near the
cutting point.
[0008] FIG. 13 shows a side elevation view of this prior art
circular power saw with optical alignment system. The laser emitter
404 is arranged, in the cutting direction, in front of the
tangential line H at an intersection G of the circumference of the
saw blade 402 and the bottom surface of the base 401. The laser
emitter 404 emits laser light beam 405 such that a light path of
the laser beam 405 contacts the saw blade 402. Moreover, the laser
emitter 404 can shift in the direction parallel to the rotation
axis of the saw blade 402 to emit the laser beam 405 to align the
optical guideline 411 on the work piece 406 generated by the laser
beam 405 with either of the side surface 412a or 412b of the saw
blade 402.
[0009] FIGS. 14A and 14B show alignment conditions in this prior
art power saw.
[0010] The operator adjusts the position of the laser emitter 404
in either of condition shown in FIG. 14 or 14B in accordance with
that the operator intends to cut the work piece 406 on either side
of the saw blade 402.
[0011] FIGS. 15A to 15E illustrate sectional views shown in the
direction E in FIG. 13. FIG. 15A shows an alignment condition of
the laser emitter 404, wherein one side surface 412a of the edge
portion 402a of the saw blade 402 is aligned with the optical
guideline 411. FIG. 15E shows an opposite alignment condition of
the laser emitter 404, wherein the other side surface 412b of the
edge portion 402a of the saw blade 402 is aligned with the optical
guideline 411. FIGS. 15B to 15D show the intermediate alignment
conditions between those in FIG. 15A and FIG. 15E. In these
alignment conditions, all guideline images have no shadow image of
edges of the saw blade on the work piece 406 because the laser
emitter 404 is arranged in front of the tangential line H in the
cutting direction CD.
[0012] This alignment operation is done with the edge of the work
piece 406 contacting the edge portion 402a of the saw blade 402 to
obtain either of alignment condition shown in FIG. 16A or FIG.
16E.
[0013] In this prior art power saw, because the laser emitter 404
is arranged in front of the tangential line H, in order to align
the laser beam 405 with either of side surface 412a or 412b, the
operator should visually observe the positional relation between
the edge portion 402a and the guideline 411 on the work piece 406
with shifting the laser emitter 404 in the direction of the
rotation axis of the saw blade 402.
[0014] FIGS. 16 and 17 show a portion of the saw blade 402, wherein
FIG. 17 shows a side elevation view of the saw blade 402 shown in
the direction F in FIG. 16. In FIGS. 16 and 17, each pair of
successive edges on the saw blade have different forms and
protrudes in opposite directions, and are alternately arranged
around the circumference of the saw blade 402. Thus, the resultant
cutting width becomes D that is a distance between the both sides
of the edges 412a and 412b. In the above-mentioned alignment
condition, the optical guideline 411 can be aligned with one side
surface 412a of an edge 402a of the saw blade 402 contacting the
edge of the work piece 406. On the other hand, the guideline 411
cannot be aligned with the other side surface 412b of edge 402b at
the same rotary position of the saw blade 402 because the edge 402b
protrudes in the opposite direction to the edge 402a and the edge
402b cannot contact the edge of the work piece 406 in that
condition. This was inconvenient.
[0015] Moreover, the operator can easily observe the side sight of
the saw blade 402 opposite to the motor because of no obstacle
structure. On the other hand, the operator cannot easily observe
the other side (the side of housing) of the saw blade 402 because
the structure blocks the sight.
SUMMARY OF THE INVENTION
[0016] The aim of the present invention is to provide a superior
portable circular power saw with optical alignment.
[0017] According to the present invention, a first aspect of the
present invention provides a portable circular power saw
comprising:
[0018] a housing;
[0019] a motor supported by said housing for rotating an attachable
saw blade for cutting a work piece;
[0020] a base supported by said housing having an opening to expose
a first portion of said circular saw blade from said base;
[0021] a saw cover supported by said housing base for covering a
second opposite portion of said saw blade;
[0022] supporting means; and
[0023] light projection means supported by said supporting means
for projecting a planer light beam to form an optical guideline on
said work piece extending in a cutting direction of saw blade,
wherein said light projection means is arranged behind, in said
cutting direction, a tangential line of said circumference of said
saw blade at an intersection of a bottom surface of said base and
said circumference at a front side of said base in said cutting
direction, and said light projection means is capable of forming
said optical guideline behind said intersection in said cutting
direction, and wherein said supporting means supports said light
projection means in respect of said saw blade slidingly in a
direction defined by a rotation axis of said saw blade.
[0024] The base has an edge extending in a direction perpendicular
to said cutting direction with a predetermined distance from said
rotation axis. The light projection means may be capable of forming
said optical guideline beyond said edge in said cutting
direction.
[0025] The light projection means may be arranged on a surface of
said saw cover opposite to said saw blade, said saw cover has a
window transparent in respect of said planer light beam with a size
and a position so as to form said optical guideline on said work
piece through said window. Moreover, the base has an edge extending
in a direction perpendicular to said cutting direction with a
predetermined distance from said rotation axis. The window may
transmit a first portion of said planer light beam and a second
portion of said planer light beam may be directly projected beyond
said edge in said cutting direction.
[0026] According to the present invention, a second aspect of the
present invention provides a portable circular power saw
comprising:
[0027] a housing;
[0028] a motor supported by said housing for rotating an attachable
saw blade for cutting a work piece;
[0029] a base supported by said housing having an opening to expose
a first portion of said circular saw blade from said base;
[0030] a saw cover supported by said housing on the opposite side
of said base for covering a second opposite portion of a
circumference of said saw blade; and
[0031] light projection means attached to said saw cover housing
for projecting a planer light beam to form an optical guideline on
said work piece extending in a cutting direction of saw blade,
wherein said saw cover has a window transparent in respect of said
planer light beam with a size and a position so as to form said
optical guideline on said work piece through said window.
[0032] The light projection means may be attached to a surface of
said saw cover opposite to said saw blade.
[0033] The window may comprise a through hole.
[0034] The light projection means may be attached to an inner
surface of said saw cover on the side of said saw blade and said
window may transmit said light beam therethrough outwardly.
[0035] The inner surface of the saw cover may have a hollow portion
outwardly protruding in a radial direction of said saw blade to
contain said light projection means.
[0036] Moreover, a loaded safety cover rotatably supported around
said circumference of said saw blade may be provided inside said
saw cover for safety covering a portion of said saw blade during
non-cutting operation and rotatably shifting under said light
projection means during cutting operation, wherein said safety
cover has a window for transmitting said light beam from said
window of said saw cover therethrough during said cutting
operation.
[0037] Moreover, a supporting means for supporting said light
projection means may be provided in respect of said saw blade
slidingly in a direction defined by a rotation axis of said saw
blade and a locking mechanism for locking said light projection
means at a given position within a predetermined sliding range.
[0038] Moreover, an externally operable shutter with a supporting
mechanism for selectively shutting said window may be provided.
[0039] According to the present invention, a third aspect of the
present invention provides a portable circular power saw
comprising:
[0040] a housing;
[0041] a motor supported by said housing for rotating an attachable
saw blade for cutting a work piece;
[0042] a base supported by said housing having an opening to expose
a portion of said circular saw blade from said base;
[0043] a saw cover supported by said housing for covering a second
opposite portion of a circumference of said saw blade; and
[0044] light projection means attached to a surface of said saw
cover opposite to said saw blade for projecting a planer light beam
to form an optical guideline on said work piece extending in a
cutting direction of saw blade, wherein said saw cover has a window
transparent in respect of said planer light beam with a size and a
position so as to form said optical guideline on said work piece
through said window and an externally operable shutter for
selectively shutting said window.
[0045] The saw cover may have a sliding mechanism for slidingly
supporting said shutter.
[0046] Moreover, a laser cover arranged on a surface of said saw
cover opposite to said saw blade may be further provided. The laser
cover may have a through hole for transmitting said light beam
through said through hole outwardly with respect to a side of said
saw blade to form another optical guideline on said work piece,
wherein said shutter is accessible through said through hole.
[0047] The portable circular power saw based on the first aspect,
may further comprise an externally operable shutter for selectively
shutting said window.
[0048] The portable circular power saw based on the second aspect,
may further comprise supporting means, wherein said light
projection means is arranged behind, in said cutting direction, a
tangential line of said circumference of said saw blade at an
intersection of a bottom surface of said base and said
circumference at a front side of said base in said cutting
direction, and said light projection means may be capable of
forming said optical guideline behind said intersection in said
cutting direction, and wherein said supporting means may support
said light projection means in respect of said saw blade slidingly
in a direction defined by a rotation axis of said saw blade and
holding said light projection means at any given position within a
predetermined sliding range.
[0049] The portable circular power saw based on the third aspect,
may further comprise supporting means, wherein said light
projection means may be arranged behind, in said cutting direction,
a tangential line of said circumference of said saw blade at an
intersection of a bottom surface of said base and said
circumference at a front side of said base in said cutting
direction, and said light projection means may be capable of
forming said optical guideline behind said intersection in said
cutting direction, and wherein said supporting means may support
said light projection means in respect of said saw blade slidingly
in a direction defined by a rotation axis of said saw blade and
hold said light projection means at any given position within a
predetermined sliding range.
BRIEF DESCRIPTION OF THE DRAWINGS
[0050] The object and features of the present invention will become
more readily apparent from the following detailed description taken
in conjunction with the accompanying drawings in which:
[0051] FIG. 1 is a side elevation view, partially a cut view, of a
potable circular power saw according to a first embodiment;
[0052] FIG. 2 illustrates an alignment condition of the potable
circuit power saw according to the first embodiment;
[0053] FIG. 3 shows a sectional view of a slidingly supporting
mechanism, taken on the line B-B in FIG. 1;
[0054] FIGS. 4A to 4E illustrate alignment conditions of the
potable circuit power saw according to the first embodiment;
[0055] FIG. 5 is a side elevation view of the portable circular
power saw in accordance with a second embodiment;
[0056] FIG. 6 is a side elevation of the portable circular power
saw according to a third embodiment;
[0057] FIG. 7 is a side elevation of the portable circular power
saw according to a fourth embodiment;
[0058] FIG. 8 is a partial sectional view of the portable circular
power saw according to a fifth embodiment;
[0059] FIG. 9 is a perspective view of the laser emitter and its
peripheral portion of the portable circular power saw according to
a fifth embodiment shown in the direction A2 in FIG. 8;
[0060] FIG. 10 is a perspective view of the laser emitter and its
peripheral portion of the portable circular power saw according to
a fifth embodiment shown in the direction B2 in FIG. 8;
[0061] FIGS. 11 and 12 illustrate a prior art portable circular
power saw;
[0062] FIG. 13 is a side view of another prior art circular power
saw with optical alignment system;
[0063] FIGS. 14A and 14B illustrate alignment conditions in another
prior art power saw;
[0064] FIGS. 15A to 15E illustrate sectional views shown in the
direction E in FIG. 13;
[0065] FIG. 16 is a partial side elevation of a prior art saw
blade; and
[0066] FIG. 17 is a partial front view of the prior art saw blade
shown in the direction F in FIG. 16.
[0067] The same or corresponding elements or parts are designated
with like references throughout the drawings.
DETAILED DESCRIPTION OF THE INVENTION
First Embodiment
[0068] FIG. 1 shows a portable circular power saw with optical
alignment. It comprises: a housing 7, a motor (not shown) supported
and contained by the housing 7 for rotating an attachable circular
saw blade 2 for cutting a work piece 6, a base 1 supported by the
housing 7 having an opening to expose a first portion of the
circular saw blade 2 from the base 1, a saw cover 3 supported by
the housing 7 for covering a second opposite portion of the saw
blade, and a laser emitter 4 as a light projection means supported
in respect of the housing 7 for projecting a planer light beam 5 to
form an optical guideline 11 on the work piece 6 extending in a
cutting direction CD of the saw blade 2.
[0069] The laser emitter (oscillator) 4 is arranged on the outer
surface of the saw cover 3 (on the surface opposite to the saw
blade 2) so as to direct the laser beam 5 to a plane defined by the
bottom surface of the base 1 (an upper surface of a work piece 6)
to form an optical guideline 11 extending in the cutting direction
CD. More specifically, the laser emitter 4 is arranged behind, in
the cutting direction CD, a tangential line H of the circumference
of the saw blade 2 at an intersection G of a bottom surface of the
base 1 and the circumference at a front side of the base 1 in the
cutting direction CD and is capable of forming the optical
guideline 11 behind the intersection G in the cutting direction and
at or beyond the edge 8 of the base 1 to have a radiation angle
range 5a in the cutting direction CD.
[0070] In this embodiment, the base 1 has an edge 8 extending in a
direction perpendicular to the cutting direction CD with a
predetermined distance (M in the cutting direction) from the
rotational axis RA of the saw blade 2. The laser emitter 4 is
capable of forming the optical guideline 11 at and beyond the edge
8 in the cutting direction CD.
[0071] The saw cover 3 has a window 3a that can transit the laser
beam 5 therethrough to form the optical guideline 11 adjacent to
the intersection G. A second portion of the laser beam 5 transmits
along the outer surface of the saw cover 3 and hits the work piece
6 to form another part of optical guideline 11 formed at or beyond
the edge 8 of the base 1.
[0072] The laser emitter 4 has a laser diode for emitting a
coherent laser beam and a toric lens for expanding the transmitting
direction to form a planer laser beam 5 extending in the cutting
direction CD for example.
[0073] The laser emitter 4 can form the optical guideline 11
extending in the cutting direction behind the intersection G. The
leaser emitter 4 can be adjustably shifted in a direction of the
rotation axis RA of the saw blade 2 with a slidingly supporting
mechanism 9.
[0074] FIG. 3 shows a sectional view of the slidingly supporting
mechanism 9, taken on the line B-B in FIG. 1.
[0075] FIG. 3 also illustrates the positional relation of the saw
blade 2 and the laser emitting point C of the laser emitter 4. That
is, the laser beam emitting point C is aligned with one side
surface 12a (housing side). The laser emitter 4 is fixed to a
sliding member 20 with a mount 4a. The sliding member 20 has screw
holes 20a and a through hole 20b at both edges thereof. A bolt 21
piercing through a through hole 22a in a fixing member 22 fixed to
the saw cover 3. Between the sliding member 20 and the fixing
member 22, coil springs 23 and 24 are arranged. Thus, the sliding
member 20 is spring-loaded such that the fixing member 22 always
pushes the sliding member 20. The fixing member 22 has a through
hole 22b in which a pin 25 is pressed and slidingly pierces a
through hole 20b in the fixing member 22.
[0076] When the bolt 21 is turned in the fastening direction, the
sliding member 20 shifts in a closer direction to the fixing member
22. Thus, the position of the laser emitter 4 is adjustable in the
direction parallel to the rotation axis RA of the saw blade 2. When
the bolt 21 is turned to the loosening direction, the sliding
member 20 shifts in the away direction from the fixing member 22.
Thus, the position of the laser emitter 4 can be adjusted.
[0077] As mentioned above, the portable circular power saw
comprises the fixing member 22, the pin 25, and the sliding member
20 as the supporting means for supporting the laser emitter 4 as
the light projection means in respect of said saw blade 2 slidingly
in a direction defined by a rotation axis RA of the saw blade 2 and
the bolt 21 and the coil springs 23 and 24 as a holding mechanism
for holding the light projection means at a given position within a
predetermined sliding range.
[0078] FIG. 2 shows the positional relation of the optical
guideline 11 and the saw blade 2 in the condition that the laser
emitting point C is aligned with the one side surface 12a of the
edge portion 2a. Turing the bolt 21 in the loosening direction from
this condition, the laser emitting point C of the laser beam 4 can
be aligned with the center of the saw blade 2 or the other side
surface of the saw blade 2.
[0079] The coil spring 23 is also provided to prevent vibrations
developed, during cutting, between a small space between the thread
of the bolt 21 and thread of the screw hole 20a.
[0080] FIGS. 4A to 4E show positional relations between the saw
blade 2 and the optical guideline 11. In FIG. 4A, the optical
guideline 11 is aligned with one side surface 12a of the edge
portion 2a. In other words, the planer laser beam 5 is aligned with
one side surface 12a of the edge portion 2a. In FIG. 4E, the
optical guideline 11 is aligned with the other side surface 12b of
the edge portion 2a. In other words, the planer laser beam 5 is
aligned with the other side surface 12b of the edge portion 2a.
FIGS. 4B to 4D show intermediate positional relations as the bolt
21 is successively turned in the loosening direction. That is, the
slidingly supporting mechanism 9 supports the laser emitter 4 in
respect of the saw blade 2 slidingly in a direction defined by a
rotation axis RA of the saw blade and holds the laser emitter 4 at
any given position within a predetermined sliding range.
[0081] During this alignment, the optical guidelines 11 in FIG. 4B
to 4D have shadows 11a of the edge portion 2a over a length L. That
is, the edge portion 2a stops a portion of the laser beam 5 behind,
in the cutting direction, the point K where the laser beam 5
tangentially contacts the edge of the edge portion 2a. The
shadowing the laser beam 5 provides positional information of both
side surfaces 12a and 12b of the edge portion 2a at any rotary
position of the saw blade 2.
[0082] This operation is provided by the structure that the laser
beam 5 is projected behind, in the cutting direction CD, the
tangential line H at the intersection G between the bottom surface
of the base 1 and the circumference of the saw blade 2 and the
laser emitter 4 can be shifted in the direction parallel to the
rotation axis RA of the saw blade 2.
[0083] The shadows 11a in FIGS. 4B to 4D are generated by that
several edges 2a above the intersection G stop a portion of the
laser beam 5. Thus, if the image of the optical guideline 11
includes a shadow 11a, the laser beam 5 is located within the width
D of the edge portion 2a.
[0084] Thus, in this portable circular power saw according to this
embodiment, when the optical guideline 11 is aligned with either of
side surfaces 12a and 12b, the operator observes whether the
optical guideline 11 has a shadow 11a or not within the length L as
shifting the laser emitter 4 in the direction of the rotational
axis RA of the saw blade 2. Thus, the operator is not required to
directly observe the side surface 12a or 12b. This operation
provides positional information of both side surfaces 12a and 12b
of the edge portion 2a in the image of the optical guideline 11 at
any rotary position of the saw blade 2. Thus, though the saw blade
2 has edges shown in FIGS. 16 and 17, wherein each pair of
successive two edges on the saw blade have different forms and
protrudes in the opposite directions alternately, the laser beam 5
is partially stopped to have guideline 11 with the shadow 11a when
the laser beam 5 is located within the width D of the edge portion
2a. Thus, the operator can adjust the optical guidelines 11 with
observing the shadow 11a in the optical guideline 11.
[0085] Moreover, because the operator is not required to observe
the side surface 12a or 12b together with the guideline 11 at the
same time, that is, the operator is required to only observe the
shape of the optical guideline 11, the operator can observe the
guideline 11 slantwise, not just above the edge portion 12a on the
plane of the saw blade 2. Thus, the operator can easily observe the
guideline 11 at the place behind, in the cutting direction CD, the
intersection G.
[0086] After the initial alignment of the laser either 4 with
either of side surfaces of the saw blade 2, the operator aligns the
optical guideline 11 with a cutting line (not shown) on the work
piece 6 to cut the work piece 6.
[0087] In this embodiment, the laser emitter 4 is arranged on the
surface of the saw cover 3 opposite to the saw blade 2 and the
window 3a is provided in the saw cover 3 to allow the laser beam 5
to transmit therethrough to form the guideline 11 behind the
intersection G in the cutting direction CD. However, the laser
emitter 4 may be arranged inside the saw cover 3, on the side of
the saw blade 2.
[0088] In the above-mentioned embodiment, the laser emitter 4 is
slidingly shifted in the direction of the rotational axis RA.
However, the position of the laser emitter may be adjusted in the
direction of the rotational axis RA by a rotating mechanism and a
mechanism keeping the perpendicular direction to the rotation axis
RA. For example, a pantograph mechanism provides this type of
position adjustment.
Second Embodiment
[0089] FIG. 5 shows a portable circular power saw in accordance
with a second embodiment. The structure of this portable circular
power saw is substantially the same as that of the first
embodiment. The difference is in that the laser emitter 105 is
arranged on the upper surface of the saw cover 103 at a position
behind, in the cutting direction CD, a tangential line L2 of the
circumference of the saw blade 2 intersecting with a connection
point 120 between the edge 121 of the base 109 and the end of the
saw cover 103 to project the laser beam 104 at the cutting point on
the upper surface of the work piece 116 through a window 106 from
the laser emitter 105.
[0090] Moreover, the laser emitter 105 is arranged behind, in the
cutting direction CD, a tangential line L1 of the circumference of
the saw blade 2 perpendicular to the bottom surface of the base 1
or the upper surface of the work piece 116. This is because during
cutting, cutting chips are hit and fly along the tangential line
102. The inclination of the tangential line 102 varies with the
thickness of the work piece 116. If a work piece 116 with the
possible greatest thickness is cut, cutting chips are hit
substantially perpendicularly to the base 1. Thus, positioning the
laser emitter 105 on the saw cover 103 behind the perpendicular
line L1 in the cutting direction CD prevents cutting chips from
sticking to the laser beam emitting point of the laser emitter 105
if the window 106 is a through hole, and prevents chips from
sticking to the window 105, if the window 105 is provided a
transparent material such as a clear plastic plate.
[0091] In this embodiment there is a further d difference in that a
safety cover 107 is further provided. The safety cover 107 is
rotationally supported in respect of the rotational axis RA of the
saw blade 101 around the circumference of the saw blade 101 to
cover a portion of the saw blade 101 on the cutting side, wherein
the safety cover 107 rotationally slide around the circumference of
the saw blade 101 between the saw cover 103 and the saw blade 101
as the end of work piece 116 enters the cutting area. On the
initial alignment, i.e., when the position of the laser emitter 105
is aligned with one of side surfaces of the edge portion of the saw
blade 101, the work piece 116 is positioned to have contact of its
edge with the edge portion of the saw blade 101. Thus, as shown in
FIG. 5, the safety cover 107 does not stop the laser beam 104
transmitted through the window 106 in the non-cutting condition.
Thus, this embodiment provides a favorable initial alignment of the
optical guidelines 110 and 111 with one of side surface of the edge
portion of the saw blade 101 with the slidingly supporting
mechanism 9.
Third Embodiment
[0092] FIG. 6 shows a portable circular power saw according to a
third embodiment. The structure of this portable circular saw has
substantially the same structure as that of the second embodiment.
The difference is in that the safety cover 107 has a window 108 at
a position entering the laser beam radiation range 104a when the
safety cover 107 is rotated around the circumference of the saw
blade 101 during cutting.
[0093] More specifically, during cutting, one end 107a of the
spring loaded safety cover 107 is pushed by the edge of work piece
116 as the saw blade 101 enters the work piece 116. When the edge
of the work piece 116 reaches the end portion 109b of the base 109,
the safety cover 107 has a maximum rotation angle and holds this
condition thereafter. In this condition, the other end 107b of the
safety cover 107 enters the laser beam radiation angle range 104a.
Thus, the window 108 is provided to allow the laser beam 104 to
pass through the window 108. In this embodiment, the window 108
comprises a through hole. Alternatively, a transparent member that
can transmit the laser beam 104 provides the window 108. Moreover,
the whole of the safety cover 107 may be made of a transparent
plastic member.
[0094] This embodiment is applicable to the first and second
embodiments.
Fourth Embodiment
[0095] FIG. 7 shows the portable circular power saw according to a
fourth embodiment. This portable circular saw has substantially the
same structure as that of the second embodiment. The difference is
in that the laser emitter 105 is mounted on and inside the saw
cover 103, that is, the laser emitter 105 is mounted on the side of
the saw blade 101 from the saw cover 103. The laser emitter 105 has
a radiation angle range 104b of the laser beam 104b covering the
portion adjacent to the cutting point 122 with the optical
guideline 111 and the portion in front (in cutting direction CD) of
the base 1 with the optical guideline 110. The optical guideline
111 is formed by direct transmission of the laser beam 104 through
the space inside the saw cover 103 and the optical guideline 110 is
formed by transmission of the laser beam 104 through a window 106
formed in the saw cover 103. That is, the laser emitter 105 is
attached to an inner surface of the saw cover 103 on the side of
the saw blade 101 and the window 106 transmits the laser beam 104
therethrough outwardly. The saw cover 103 has a hollow portion 103a
outwardly protruding in a radial direction of the saw blade 101 to
contain the laser emitter 105.
Fifth Embodiment
[0096] FIG. 8 shows a laser emitter 212 and its peripheral portion
of the portable circular power saw according to a fifth embodiment.
The structure of this portable circular saw has substantially the
same structure as that of the third embodiment. The difference is
in that the window 207 in the saw cover 206 has a slide cover 201.
The slide cover 201 selectively covers the window 207 to prevent
the cutting chips from attaching to the laser beam emitting point
213 of the laser emitter 212.
[0097] More specifically, a laser cover 202 is arranged on the
upper surface of the saw cover 206. The laser emitter 212 has a
laser beam radiation angle range covering the portion adjacent to
the cutting point and the portion in front (in cutting direction
CD) of the base in the same way as the fourth embodiment. The laser
emitter 212 is fixed to the laser cover 202 through the slidingly
supporting mechanism 9. The window 207 comprising a through hole
and is arranged to allow the laser beam to pass therethrough to
form the optical guideline adjacent to the cutting point. The laser
cover 202 has a through hole 202a arranged to pass the laser beam
therethrough to form the optical guideline on a portion in front
(in the cutting direction CD) of the base. The slide cover 201 is
accessible through the through hole 202a to selectively shut the
window 207.
[0098] The slide cover 201 is made of plastic and is attached to a
rail 205 to slide along the longitudinal direction of the rail
205.
[0099] As shown in FIG. 8, the slide cover 201 has a groove portion
201a capable of covering three surfaces of the rail 205. Thus, the
slide cover 201 is attached to laser cover 202 through the rail 205
by fitting the inside the groove portion 201a in the rail 205.
[0100] The slide cover 201 has a width and length capable of
covering the window 207. Thus, the slide cover 201 can selectively
shut the window.
[0101] FIG. 9 shows a perspective view of the portion including the
slide cover 201 viewed in the direction A2 in FIG. 8. FIG. 10 shows
a perspective view of the portion including the slide cover 201
viewed in the direction B2 in FIG. 8.
[0102] The slide cover 201 has a protruding guide rail 201b
covering a groove 205a in the rail 205. The protruding guide rail
201b fits into the groove 205a to prevent the slide cover 201 from
detaching from the rail 205. The protruding guide rail 201b is
fitted into the groove 205 through elastic deformation of the slide
cover.
[0103] The protruding guide rail 201b has a protuberance 201d
having a semicircle cross-sectional shape. On the other hand, the
groove 205a has notches 205b and 205c having corresponding
semicircle cross-sectional shape at the shutter position and the
open position of the slide cover 201, respectively.
[0104] Thus, the protuberance 201d fitting into the notch 205b in
the groove 205a holds the slide cover 201 at the shutter position.
On the other hand, the protuberance 201c fitting into the notch
205c in the groove 205a holds the slide cover 201 at the open
position. The protuberance 201d and the notches 205b and 205c
provide stop positions in sliding action of the slide cover 201 and
prevents the slide cover 201 from unintentional movement due to
vibration during cutting.
[0105] The groove portion 201a is outwardly protruded and is
accessible through the 202a. Thus, the operator can access to the
groove portion 201a and can slide the slide cover by pushing the
groove portion 201 to open or shut the window 207.
[0106] The slide cover 201 can be removed from the rail 205 by
lifting one end 201e, that is, in FIG. 9, rotating the slide cover
201 around the rail 205 clockwise. On the other hand, the slide
cover 201 has a extending portion 201C which limits the rotation of
the slide cover 201 to prevent unintentional removal of the slide
cover 201.
[0107] According to this embodiment, the window 207 is selectively
shut or opened in accordance with the cutting condition. More
specifically, though a work piece includes much moisture or much
resin, the operator can shut the window 207 to protect the laser
beam emitting portion 213 during cutting. In this condition, the
operator can align the cutting line on the work piece with the
optical guideline formed in front of the base.
[0108] Moreover, the operator can align the cutting line on the
work piece with the optical guideline around the cutting point with
the window 207 opened before the start of cutting. Thus, at first,
the operator aligns the optical guideline with the cutting line on
the work piece, and then, shuts the slide cover 201 before the
start of cutting. Accordingly, this structure does not decrease the
efficiency in the alignment operation between the cutting line and
the optical guideline.
[0109] Moreover, the slide cover 201 is detachable, so that the
operator can clean the sliding cover 201, if many cutting chips
attach to the slide cover 201.
[0110] In this embodiment, the slide cover 201 can slide along the
rail 205 extending in the rotation axis RA of the saw blade.
However, the slide cover may have a sliding mechanism for sliding
the cover in the direction perpendicular to the rotational axis RA
of the saw blade. Moreover, the slide cover 201 may have a slide
mechanism capable of rotational movement of the slide cover 201 at
the shutter position and the open position.
[0111] Moreover, the slide cover may comprise a transparent plastic
member. In this case, the laser beam can be projected at the
portion around the cutting point though the slide cover is in the
shutter position.
[0112] Moreover, the slide cover 201 according to this embodiment
is applicable to the first to fourth embodiments.
* * * * *