U.S. patent application number 11/519942 was filed with the patent office on 2007-03-15 for cutting devices.
This patent application is currently assigned to MAKITA CORPORATION. Invention is credited to Yoshinori Shibata.
Application Number | 20070056416 11/519942 |
Document ID | / |
Family ID | 37853740 |
Filed Date | 2007-03-15 |
United States Patent
Application |
20070056416 |
Kind Code |
A1 |
Shibata; Yoshinori |
March 15, 2007 |
Cutting devices
Abstract
A cutting including a saw blade protruding from an upper surface
of the table can include a splitter positioned on the front side
with respect to a cutting direction of the saw blade and in
alignment with the saw blade. A guard device is provided for
covering the saw blade. A kickback preventing claw member prevents
the workpiece from being forced upward by the saw blade after the
workpiece has been cut by the saw blade. A mount frame is
detachably mounted to an upper portion of the splitter. The guard
device and the kickback preventing claw member are supported on the
mount frame, so that the guard device and the kickback preventing
claw can be removed separately or together from the splitter.
Inventors: |
Shibata; Yoshinori;
(Anjo-shi, JP) |
Correspondence
Address: |
OLIFF & BERRIDGE, PLC
P.O. BOX 19928
ALEXANDRIA
VA
22320
US
|
Assignee: |
MAKITA CORPORATION
ANJO-SHI
JP
|
Family ID: |
37853740 |
Appl. No.: |
11/519942 |
Filed: |
September 13, 2006 |
Current U.S.
Class: |
83/440.2 |
Current CPC
Class: |
Y10S 83/01 20130101;
B23D 47/04 20130101; Y10T 83/773 20150401; B27G 19/08 20130101;
Y10T 83/2077 20150401; Y10T 83/732 20150401; Y10T 83/7734 20150401;
B27G 19/02 20130101; Y10T 83/872 20150401 |
Class at
Publication: |
083/440.2 |
International
Class: |
B26D 7/06 20060101
B26D007/06 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 15, 2005 |
JP |
2005-268614 |
Claims
1. A cutting device comprising: a table for placing a workpiece
thereon; a saw blade protruding from an upper surface of the table;
a splitter positioned in alignment with the saw blade; a guard
device arranged and constructed to cover the saw blade; a kickback
preventing claw member arranged and constructed to prevent the
workpiece from being forced upward by the saw blade after the
workpiece has been cut by the saw blade; and a mount frame
detachably mounted to an upper portion of the splitter; wherein the
guard device and the kickback preventing claw member are supported
on the mount fame, so that the guard device and the kickback
preventing claw member can be removed from the splitter.
2. The cutting device as in claim 1, wherein the guard device
capable of being removed separately from the mount frame.
3. The cutting device as in claim 2, wherein: the mount frame
comprises a tubular portion with an opening on a rear side with
respect to the cutting direction, further wherein the guard device
comprises a mount holder removably insertable into the tubular
portion, a guard frame extending rearward from the mount holder
with respect to the cutting direction, a guard holder disposed at
one end of the guard frame, and a guard plate vertically pivotally
supported on the guard holder.
4. The cutting device as in claim 1, wherein: the splitter includes
a first slot starting from an upper edge of the splitter and having
a first width, and a second slot formed in continuity with the
first slot and having a second width greater than the first width,
further wherein the mount frame includes a mount mechanism for
mounting the mount frame to an upper portion of the splitter; the
mount mechanism comprises: a lever vertically pivotally supported
by the mount frame via a fixed shaft; an arm having a first end and
a second end, wherein the first end is pivotally joined to the
lever; a shiftable shaft coupled to the second end of the arm and
movably supported by the mount frame, so that the shiftable shaft
moves in forward and rearward directions as the arm pivots by the
vertical pivotal operation of the lever, a first engaging roller
rotatably supported on the fixed shaft; a second engaging roller
rotatably supported on the shiftable shaft, so that the second
engaging roller moves toward and away from the first engaging
roller as the lever is pivoted between a first position and a
second position; wherein the first and second engaging rollers are
spaced from each other by a first distance when the lever has been
pivoted to the first position; and wherein the first and second
engaging rollers are spaced from each other by a second distance
when the lever has been pivoted to the second position; the first
distance permitting the first and second engaging rollers to move
into and out of the second slot via the first slot of the splitter
when the lever has been pivoted to the first position; and the
second distance enabling engagement of the first and second rollers
with opposite ends of the second slot of the splitter when the
lever has been pivoted to the second position, while the second
distance preventing the first and second engaging rollers from
moving from the second slot to the first slot.
5. The cutting device as in claim 1, further comprising: a lift
base supporting the saw blade and vertically movable relative to
the table; wherein the splitter is mounted to the lift base via a
mount base, so that the splitter can move vertically together with
the saw blade; wherein the mount base comprises: a fixed base
fixedly mounted to the lift base, a clamp plate arranged and
constructed to clamp the splitter against the fixed base; and a
biasing member arranged and constructed to bias the clamp plate
toward the fixed base.
6. The cutting device as in claim 1, wherein the kickback
preventing claw member is vertically pivotally supported by the
mount frame and is pivotable between a lower kickback preventing
position and an upper rest position, wherein the cutting device
further comprises a claw holding spring for resiliently holding the
kickback preventing claw member at the upper rest position.
7. The cutting device as in claim 6, wherein the mount frame
comprises a pair of parallel protection arms extending forwardly
from the mount frame with respect to the cutting direction, and
wherein the claw holding spring is disposed between the protection
arms, so that the kickback preventing claw member extends along and
between the protection arms when the kickback preventing claw
member is positioned in the upper rest position.
8. A cutting device comprising: a table for placing a workpiece
thereon; a circular saw blade partially protruding upward from an
upper surface of the table; a splitter arranged and constructed to
enter a cut formed in the workpiece by the saw blade in order to
prevent interference between the saw blade and the workpiece at the
cut; a saw blade guard arranged and constructed to cover the saw
blade; a workpiece holding member arranged and constructed to hold
the workpiece against the upper surface of the table in order to
prevent the workpiece from being move at least in one direction a
mount member; a first mount mechanism detachably mounting the mount
member to the splitter; a second mount mechanism mounting the saw
blade guard to the mount member; a third mount mechanism mounting
the workpiece holding member to the mount member.
9. The cutting device as in claim 8, wherein the second mount
mechanism detachably mounts the saw blade guard to the mount
member.
10. The cutting device as in claim 9, wherein the second mount
mechanism comprises a mount holder detachably mounted to the mount
member, and wherein the saw blade guard is vertically pivotally
mounted to the mount holder.
11. The cutting device as in claim 10, wherein the saw blade guard
comprises a first guard and a second guard individually pivotally
mounted to the mount holder between a covering position for
covering the saw blade and an uncovering position for uncovering
the saw blade, wherein the first guard and the second guard are
moved by the workpiece from the covering position to the uncovering
position at different timing from each other as the workpiece moves
along the table surface toward the saw blade for the cutting
operation.
12. The cutting device as in claim 11, further comprising a first
holding device for releasably holding the first and the second
guards in the uncovering position.
13. The cutting device as in claim 8, wherein the third mounting
mechanism vertically pivotally mounts the holding member to the
mount member, so that the holding member can move between a holding
position for holding the workpiece against the table surface and a
rest position away from the holding position.
14. The cutting device as in claim 13, further comprising a second
holding device for releasably holding the holding member in the
rest position.
15. The cutting device as in claim 14, wherein the mount member
comprises a protection member mounted to the mount member for
preventing the holding member from interference with the other
elements when the holding member is in the rest position.
16. The cutting device as in claim 8, wherein the first mount
mechanism comprises a slot formed in the splitter and an engaging
device releasably engageable with the slot in order to fix the
mount member in position relative to the splitter.
17. The cutting device as in claim 16, wherein the engaging device
comprises: a first engaging member and a second engaging member
attached to the mount member, wherein at least one of the first and
second engaging members is movable relative to the mount member; an
operation member movable between a first position and a second
position and provided to move the at least one of the first and
second engaging members; wherein the first and second engaging
members are spaced from each other by a first distance, so that the
first and second engaging members can be inserted into and removed
from the slot of the splitter when the operation member is operated
to the first position, wherein the first and second engaging
members are spaced from each other by a second distance, so that
the first and second engaging members positioned in the slot of the
splitter is fixed when the operation member is moved to the second
position;
18. The cutting device as in claim 17, further comprising a lock
device for the operation member and operable to fix the second
distance between the first and second engaging members when the
operation member is in the second position.
Description
[0001] This application claims priority to Japanese patent
application serial number 2005-268614, the contents of which are
incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to cutting devices, and in
particular to table saws having a table for placing workpieces
thereon and a saw blade partially protruding upward from the upper
surface of the table.
[0004] 2. Description of the Related Art
[0005] Table saws have a table for placing workpieces thereon and a
circular saw blade that partially protrudes upward from the upper
surface of the table, so that workpieces may be cut by moving
workpieces along the upper surface of the table toward the saw
blade in a direction parallel to the surface of the saw blade. It
has been known to provide a guard device in order to prevent
potential interference of the other articles with the upper portion
of the saw blade protruding from the table surface. The known guard
device has a guard plate that is configured to cover the saw blade
primarily from right and left sides and the upper side. The guard
device is configured such that the guard plate is moved upward or
opened by the Workpiece as the workpiece moves toward the saw
blade. Typically, the guard plate is vertically pivotally mounted
to a splitter.
[0006] For the convenience of change of the saw blade, there has
been proposed to configure the guard device such that the guard
plate can not only vertically pivot but also can be completely
removed. Japanese Laid-Open Utility Model Publication No. 646901,
U.S. Pat. No. 6,405,624 and EP 1491304 A2 teach known guard
devices.
[0007] In general, a saw blade of the table saw rotates in such a
direction that the saw blade moves downward on the side of the
position of the workpiece before it is cut (hereinafter called
"front side with respect to cutting direction"), while the saw
blade moves upward on the side of the position of the workpiece
after it has been cut (hereinafter called "rear side with respect
to cutting direction"). Therefore, if the cut surfaces of the
workpiece contact the rear side of the rotating saw blade
immediately after the workpiece has been cut, the workpiece may be
forced upward by the rotating saw blade in some occasion. This
phenomenon is called "kickback phenomenon." When this phenomenon
occurs, it is difficult to smoothly perform the cutting operation.
Therefore, there has been proposed to position a splitter (also
called "riving knife") having substantially the same thickness as
the saw blade on the rear side of the saw blade and within the same
plane as the saw blade. The splitter may enter the cut of the
workpiece and maintain the cut width of the workpiece in order to
avoid contact of the rotating saw blade with the cut surfaces. In
addition, in order to prevent the potential kickback phenomenon,
there has been proposed to provide kickback preventing claw members
on opposite sides of the splitter within a region where the
kickback preventing claw members may not interfere with the
movement of the workpiece in the cutting direction. Japanese
Laid-Open Utility Model Publication No. 3-42602 and U.S. Pat. No.
6,405,624 teach known kickback preventing claw members.
[0008] Also there has been proposed to provide a splitter and
kickback preventing claw members for preventing the kickback
phenomenon in addition to a guard device for preventing
interference of other articles with the saw blade. In this
structure, a guard plate of the guard device and kickback
preventing claw members are respectively vertically pivotally
supported on the upper portion of the splitter.
[0009] However, for example, in the case of the cutting operation
of a decorative laminated sheet, it would be preferable that the
kickback preventing claw members will not contact the sheet during
the cutting operation. Therefore, by configuring the kickback
preventing claw members to be able to be removed from the splitter,
the operability for this kind of cutting operation can be improved.
In addition, the operation for changing the saw blade can be
conveniently performed if the kickback preventing claw members are
removed from the splitter in order to keep the kickback preventing
claw members as far away from the saw blade as possible.
[0010] In this structure, the guard plate of the guard device and
each of the kickback preventing claw members are individually
supported on the splitter. In this configuration, a problem occurs
such that the mounting and removing operations of the guard plate
and the kickback preventing claw members are very difficult when
such operations are necessary for changing the saw blade.
SUMMARY OF THE INVENTION
[0011] One embodiment of the present invention is an improved
cutting device constructed to reduce potential troubles in
performing the operations for removing a guard device and a
kick-back preventing claw member from a splitter.
[0012] In another embodiment of the present invention, cutting
devices are taught that include a table for placing a workpiece
thereon, and a saw blade protruding from an upper surface of the
table. A splitter positioned on the front side with respect to a
cutting direction of the saw blade and in alignment with the saw
blade. A guard device is provided for covering the saw blade. A
kickback preventing claw member prevents the workpiece from being
forced upward by the saw blade after the workpiece has been cut by
the saw blade. A mount frame is detachably mounted to an upper
portion of the splitter. The guard device and the kickback
preventing claw member are supported on the mount frame, so that
the guard device and the kickback preventing claw can be removed
together from the splitter.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is a side view of a table saw according to one
embodiment of the present invention;
[0014] FIG. 2 is an enlarged side view of a portion around a saw
blade of the table saw;
[0015] FIG. 3 is a plan view as viewed from a direction indicated
by an arrow (3) in FIG. 2;
[0016] FIG. 4 is a vertical sectional view showing the state where
a mount holder of a guard device has been inserted into a mount
frame;
[0017] FIG. 5 is a vertical sectional view similar to FIG. 4 but
showing the state where the mount holder is being removed from the
mount frame;
[0018] FIG. 6 is a plan view as viewed from a direction indicated
by an arrow (6) in FIG. 4;
[0019] FIG. 7 is a side view of the guard device after removal from
the mount fame:
[0020] FIG. 8 is a rear view of the guard device with first and
second guard plates shown in vertical sectional views;
[0021] FIG. 9 is a side view of a mount mechanism and showing the
state where a mount frame has been mounted to a splitter,
[0022] FIG. 10 is a side view similar to FIG. 9 but showing the
state where the mount frame has been removed from the splitter;
[0023] FIG. 11 is a horizontal sectional view of the mount
mechanism;
[0024] FIG. 12 is a side view of the mount mechanism and also
showing kickback preventing claw members;
[0025] FIG. 13 is a side view of the splitter and showing the state
where the mount frame has been removed from the splitter;
[0026] FIG. 14 is a vertical sectional view showing a mount base
and the splitter mounted thereto; and
[0027] FIG. 15 is a plan view showing the mount base and the
splitter.
DETAILED DESCRIPTION OF THE INVENTION
[0028] Each of the additional features and teachings disclosed
above and below may be utilized separately or in conjunction with
other features and teachings to provide improved cutting devices.
Representative examples of the present invention, which examples
utilize many of these additional features and teachings both
separately and in conjunction with one another, will now be
described in detail with reference to the attached drawings. This
detailed description is merely intended to teach a person of skill
in the art further details for practicing preferred aspects of the
present teachings and is not intended to limit the scope of the
invention. Only the claims define the scope of the claimed
invention. Therefore, combinations of features and steps disclosed
in the following detailed description may not be necessary to
practice the invention in the broadest sense, and are instead
taught merely to particularly describe representative examples of
the invention. Moreover, various features of the representative
examples and the dependent claims may be combined in ways that are
not specifically enumerated in order to provide additional useful
embodiments of the present teachings.
[0029] Various embodiments of the present invention will now be
described with reference to FIGS. 1 to 15. The FIG. 1 shows an
overall view of a cutting device 1 according to one embodiment. In
this embodiment, the cutting device 1 is embodied as a table saw.
The cutting device 1 is characterized in a support structure for
supporting kickback preventing claw members 60 and a guard device
50.
[0030] Referring to FIG. 1, a table 2 is supported substantially
horizontally by a base structure 10. A circular saw blade 3 is
positioned substantially centrally of the table 2 and has an upper
portion extending from the upper surface of the table 2. The saw
blade 3 is supported by a lift base 5 disposed below the table 2 so
as to be rotatably driven by an electric motor 7. The lift base 5
is slidably supported by vertical rods 6 that are mounted on the
base structure 10, so that the lift base 5 can move in parallel in
the vertical direction. By vertically moving the lift base 5, it is
possible to change the protruding distance of the upper portion of
the saw blade 3 from the upper surface of the table 2. In other
words, it is possible to change the cutting depth of the saw blade
3 into a workpiece W.
[0031] The workpiece W can be cut as it is moved in a direction
indicated by an outline arrow (hereinafter called "cutting
direction") along the upper surface of the table 2. A splitter 20
is disposed on the front side (left side as viewed in FIG. 1) of
the saw blade 3 with respect to the cutting direction. The splitter
may be also called "riving knife."
[0032] The splitter 20 is made of a flat plate having a thickness
substantially equal to the thickness of the saw blade 3 and is
positioned within the same plane as the saw blade 3. The splitter
20 is mounted on a base portion 5a of the lift base 5 via a mount
base 25 in such a manner that the upper portion of the splitter 20
protrudes upward from the upper surface of the table 2. The
splitter 20 is adapted to enter the cut just after the cut has been
foxmed in the workpiece W in order to keep the cut width constant.
Therefore, opposite cut surfaces are prevented from contacting with
the rotating saw blade 3, so that a phenomenon called "kickback
phenomenon" can be avoided.
[0033] The kickback preventing claw members 60 and the guard device
50 are mounted to the upper end of the splitter 20, which protrudes
upward from the upper surface of the table 2, via a mount frame 30.
The mount frame 30 and the guard device 50 are shown in detail in
FIGS. 2 to 9.
[0034] The mount frame 30 includes a tubular portion 30T disposed
on the rear side thereof with respect to the cutting direction
(left side as viewed in FIG. 2). The tubular portion 30T has a
rectangular cross section and includes a top part 30a, a left part
30b, a right part 30c and a bottom part 30d The top part 30a, the
left part 30b and the right part 30c extend forwardly with respect
to the cutting direction to form an inverted U-shape portion 30U.
The left and right parts 30b and 30c further extend forwardly to
form protection arms 30e and 30f that are parallel to each other.
The front ends of the protection arms 30e and 30f are joined to
each other via a joint, to which two claw-retaining springs 61 are
attached. The function of the claw-retaining springs 61 will be
described later.
[0035] The guard device 50 is removably mounted to the tubular
portion 30T of the mount frame 30 configured as described above.
The guard device 50 in the removed state from the tubular portion
30T is shown in FIG. 7. The guard device 50 has a mount holder 51
insertable into the tubular portion 30T, a guard frame 52 extending
rearwardly with respect to the cutting direction from the mount
holder 51 (rightward as viewed in FIG. 7), a guard holder 53
disposed at the front end of the guard frame 52, a pair of right
and left first guard plates 55 and a pair of right and left second
guard plates 56. The first guard plates 55 and the second guard
plates 56 are vertically pivotally supported by the guard holder 53
via a support rod 54.
[0036] As shown in FIGS. 4 to 7, the mount holder 51 has a
substantially rectangular parallelepiped hollow configuration and
is insertable into the tubular portion 30T without producing
substantial clearance. Preferably, the mount holder 51 is
manufactured into one piece by a molding process of a synthetic
resin. A removing operation lever 51a is vertically movably
disposed on the upper portion of the mount holder 51. The removing
operation lever 51a is molded integrally with the upper portion of
the mount holder 51 while the removing operation lever 51a being
delimited from the upper portion of the mount holder 51 by a cut
line. Because the removing operation lever 51a is made of a
synthetic resin same as the mount holder 51, the removing operation
lever 51a has a resiliency in the vertical direction. When in the
state where no load is applied to the removing operation lever 51a,
the removing operation lever 51a is held to extend substantially
flush with the upper portion of the mount holder 51 as shown in
FIG. 4. When a load is applied to press the removing operation
lever 51a downwards the removing operation lever 51a may pivot
downward due to the resilient deformation of its base end joined to
the upper portion of the mount holder 51. When the pressing force
has been released, the removing operation lever 51a resiliently
recover the position to extend substantially flush with the upper
portion of the mount holder 51.
[0037] An insertion preventing stop 51c and a removal preventing
stop 51b are formed integrally with the upper surface of the
removing operation lever 51a. As shown in FIG. 4, as the mount
holder 51 is inserted into the tubular portion 30T of the mount
frame 30, the insertion preventing stop 51c may engage with the
rear end of the top part 30a defining the rear opening of the
tubular portion 30T, so that no further inserting movement of the
mount holder 51 may be restricted. In addition, in this inserted
position, the removal preventing stop 51b may enter and engages a
stop hole 30b formed in the top part 30a of the tubular portion
30T, so that the mount holder 51 may be prevented from being
removed from the tubular portion 30T. In this way, it is possible
to maintain the mounted state of the guard device 50 to the mount
frame 30.
[0038] Wen the removing operation lever 51a has been pressed
downward, the removal preventing stop 51b moves downward so as to
be removed from the stopper hole 30b, so that the mount holder 51
can be removed from the tubular portion 30T as shown in FIG. 5.
With the mount holder 51 removed from the tubular portion 30T, it
is possible to remove the guard device 50 from the mount frame
30.
[0039] A stop wall 51d is formed on the rear end (right end as
viewed in FIGS. 4 and 5) of the mount holder 51 and extends
downward therefrom. When the mount holder 51 is in the mounted
position shown in FIG. 4, the stop wall 51d substantially contacts
the rear end of the bottom part 30d of the tubular portion 30T, so
that the inserting movement of the mount holder 51 is restricted
also by the stop wall 51d.
[0040] The mount holder 51 is fixedly attached to the front end of
the guard fame 52. In other words, the guard frame 52 extends
rearward from the mount holder 51. When the guard device 50 has
been mounted to the mount frame 30 and eventually to the splitter
20, the guard frame 52 is held to horizontally extend rearward from
the mount holder 51.
[0041] The guard frame 52 can be formed by a single round bar that
is bent to have a substantially U-shape configuration elongated
along the central axis of U-shape. Opposite ends 52a of the guard
frame 52 are respectively inserted into and engaged with engaging
holes 51e formed in the mount holder 51. In addition, the parallel
leg portions of the guard frame 52 are respectively fitted into
engaging recesses 51f that are formed in opposite sides of the
mount holder 51 and extend in forward and rearward directions. With
this arrangement, the guard frame 52 is fixed in position relative
to the mount holder 51 in such a state that the guard frame 52
extends reward from the mount holder 51. A strip plate instead of a
round bar may be bent into U-shape to form the guard frame 52.
[0042] As shown in FIGS. 2, 3 and 7, the guard holder 53 can be
held by the rear end (right end as viewed in FIG. 2) of the guard
frame 52 so as to be fixed in position relative thereto. The guard
holder 53 can include a support shaft 54 that has opposite ends
extending laterally outward from the guard holder 53. The pair of
the first guard plates 55 and the pair of the second guard plates
56 are vertically pivotally supported by the opposite ends of the
support shaft 54. The first guard plates 55 are arranged
symmetrically to each other. Also, the second guard plates 56 are
arranged symmetrically to each other. The first and second guard
plates 55 and 56 may serve to cover the saw blade 3 from opposite
sides with respect to the lateral direction. More specifically, the
second guard plates 56 are designed so as to lap over the
respective first guard plates 55 from the laterally outer side.
[0043] Stopper edges 55a are respectively formed on the upper
portions of the first guard plates 55 in substantially the central
position along the forward and rearward directions (right and left
directions as viewed in FIG. 7) and extend toward each other. As
shown in FIG. 3, the stopper edges 55a can contact the guard frame
52 from its upper side in order to limit the lower pivotal stroke
end of the first guard plates 55.
[0044] Similarly, stopper edges 56a are respectively formed on the
upper portions of the second guard plates 56 in a position nearer
to their pivotal axis and extend toward each other. The stopper
edges 56a may contact the upper edges of the first guide plates 55
in order to limit the lower pivotal stroke end of the second guard
plates 56 relative to the first guard plates 55.
[0045] In the state shown in FIG. 2, where the guard device 50 has
been mounted to the splitter 20 but a workpiece W still has not
been set on the table 2, the stopper edges 55a of the first guard
plates 55 contact with the guard frame 52 from the upper side, so
that the first guard plates 55 are positioned in the lower pivotal
stroke end. In this lower pivotal stroke end, the first guard
plates 55 do not contact the upper surface of the table 2, while
the lower edges of the second guard plates 56 are in contact with
the upper surface of the table 2. Therefore, the stopper edges 56a
of the second guard plates 56 are not in contact with the upper
edges of the first guard plates 55.
[0046] As the workpiece W is moved in the cutting direction after
setting on the upper surface of the table 2, the front end of the
workpiece W may force to pivot the second guard plates 56 upward.
In other words, the second guard plates 56 are opened in order to
permit movement of the work piece W. If the workpiece W has a
relatively large thickness, the front end of the workpiece W may
further force to pivot the first guard plates 55 upward to open the
same. As described previously, the guard plates 55 and 56 can pivot
about the support shaft 54 or pivot about the same axis.
[0047] In addition, as shown in FIGS. 7 and 8, a stopper projection
56b and an interlocking stepped portion 56c are formed on each of
the second guard plates 56. When the second guard plates 56 have
been pivoted upward by a predetermined angle, the interlocking
stepped portions 56c engage the lower edges of the respective first
guard plates 55. Therefore, as the second guard plates 56 further
pivot upward by the movement of the workpiece W, the first guard
plates 55 may pivot upward together with the second guard plates
56.
[0048] Further, if the operator manually pivots the second guard
plates 56 upward together with the first guard plates 55 by a large
angle greater than the predetermined angle, the stopper projections
56b can engage the respective leg portions of the guard frame 52
from the upper side by the resilient deformation of portion of the
second guard plates 56 about the stopper projections 56b. With the
stopper projections 56b thus engaged with the respective leg
portions of the guard frame 52, the first and second guard plates
55 and 56 are temporarily held in fully opened positions. The fully
opened positions are indicated by dashed-two dotted lines in FIG.
7.
[0049] Although the first guard plates 55 and the second guard
plates 56 are provided in pairs in this embodiment, one first guard
plate and one second guard plate can be provided, or three or more
first guard plates and three or more second guard plates can be
provided.
[0050] A mount mechanism 40 can be disposed within the inverted
U-shape portion 30U of the mount frame 30. As described previously,
the U-shape portion 40U is positioned substantially centrally of
the mount frame 30 with respect to the forward and rearward
directions. The details of the mount mechanism 40 are shown in
FIGS. 9 to 11. The mount mechanism 40 has a lever 41 that can be
pivoted by the operator. The lever 41 is pivotally supported by a
fixed shaft 42 that extends between the left part 30b and the right
part 30c of the mount frame 30. The upper portion of the lever 41
extends upward through and beyond the top part 30a of the mount
frame 30. In this embodiment, lever 41 is vertically pivotally
supported by fixed shaft 42.
[0051] Also, a front engaging roller 47 is rotatably supported by
the fixed shaft 42. A pivotal shaft 43 can be mounted to the lever
41 in a position away from its pivotal axis, so that the pivotal
shaft 43 can be positioned away from the fixed shaft 42 by a
predetermined distance. An intermediate engaging roller 48 can be
rotatably supported by the pivotal shaft 43. One end of an arm 44
is vertically pivotally supported by the pivotal shaft 43. A
shiftable shaft 45 can be attached to the other end of the arm 44.
A rear engaging roller 46 is rotatably supported by the shiftable
shaft 45.
[0052] Opposite ends of the shiftable shaft 45 are slidably
inserted into control slots 30h and 30i that are respectively
formed in the left part 30b and the right part 30c of the mount
frame 30. The control slots 30h and 30i are elongated in forward
and rearward directions, so that the shiftable shaft 45 can move
together with rear engaging roller 46 in parallel in forward and
rearward directions (left and right directions as viewed in FIGS. 9
to 11) along the control slots 30h and 30i within a predetermined
range. As shown in FIG. 10, the fixed shaft 42 is positioned within
a plane J, within includes the longitudinal axes of the control
slots 30h and 30i.
[0053] Therefore, as the lever 41 pivots upward about the fixed
shaft 42, the arm 44 pivots in a clockwise direction as viewed in
FIG. 10 about the pivot shaft 43, so that the shiftable shaft 45
moves forward together with the rear engaging roller 46 along the
control slots 30h and 30i. Therefore, the rear engaging roller 46
moves toward the front engaging roller 47.
[0054] On the contrary, as the lever 41 pivots downward about the
fixed shaft 42, the arm pivots in a counterclockwise direction as
shown in FIG. 9, so that the rear engaging roller 46 moves away
from the front engaging roller 47. In addition, the intermediate
engaging roller 48 moves downward to interleave between the front
engaging roller 47 and the rear engaging roller 46 and may force
the rear engaging roller 46 to move the same rearward. As the lever
41 is further pivoted downward, the pivotal shaft 43 supporting the
intermediate engaging roller 48 moves across the plane J from a
position above the plane J to a position slightly below the plane
J. Then, the rear engaging roller 46 may be temporarily locked in a
position that is away from the front engaging roller 47. The
position of the lever 41 in this state will be hereinafter called
"lock position." In this way, the plane J defines a dead point of
the lock mechanism constituted by three engaging rollers 46, 47 and
48. The locking operation of these three engaging rollers 46, 47
and 48 by the operation of the lever 41 will be explained
later.
[0055] Forcibly pivoting the lever 41 upward from the lock position
may move the pivotal shaft 43 from the position below the plane J
to a position above the plane J, so that the lock condition may be
released and the rear engaging roller 46 can move toward the front
engaging roller 47.
[0056] As shown in FIG. 11, a circumferential engaging recess 47a
and a circumferential engaging recess 46a are respectively formed
in the outer circumferential surfaces of the front engaging roller
47 and the rear engaging roller 46 throughout their circumferential
lengths. Preferably, each of the engaging recesses 47a and 46a can
have a substantially V-shape cross section and can have a maximum
width that is slightly greater than the thickness of the splitter
20. A circumferential engaging projection 48a engageable with the
circumferential recess 46a of the rear engaging roller 46 can be
formed on the outer circumferential surface of the intermediate
engaging roller 48. Preferably, the engaging projection 48a has a
width that is substantially equal to the thickness of the splitter
20.
[0057] For cooperating with the mount mechanism 40 configured as
described above, a first slot 20a and a second slot 20b can be
formed in the upper portion of the splitter 20. The first slot 20a
extends into the splitter 20 from the upper edge of the splitter 20
as shown in FIG. 20, so that the first slot 20a has an upper
opening having a width L1 with respect to forward and rearward
directions. The second slot 20b is formed in continuity with the
lower portion of the first slot 20a and is elongated in forward and
rearward directions, so that the second slot 20b has a width L2
that is greater than the width L1 (L2>L1).
[0058] As the lever 41 is pivoted upward to move the rear engaging
roller 46 toward the front engaging roller 47, the distance between
the front side portion of the front engaging roller 47 and the rear
side portion of the rear engaging roller 46 may be reduced to be
smaller than the width L1. Therefore, with the distance thus
reduced, the front and rear engaging rollers 47 and 46 can enter
the first slot 20a of the splitter 20 and further enter the second
slot 20b. Then, the operator may pivot the lever 41 downward to
move the rear engaging roller 46 away from the front engaging
roller 47, so that the rear engaging roller 46 engages the rear end
of the second slot 20b and the front engaging roller 47 engages the
front end of the second slot 20b. As the lever 41 is further
pivoted downward to the lock position, the intermediate engaging
roller 48 presses the front and rear engaging rollers 47 and 46
against portions of the splitter 20, which define front and rear
ends of the second slot 20b. As a result, the mount mechanism 40
can be held to be mounted to the splitter 20.
[0059] More specifically, in this lock condition, the distance
between the front side portion of the front engaging roller 47 and
the rear side portion of the rear engaging roller 46 is greater
than the width L1 of the first slot 20a. Therefore, these engaging
rollers 47 and 46 are restricted from moving through the first slot
20a. In addition, portions of the splitter 20 defining the front
and rear ends of the second slot 20b engages the engaging recesses
47a and 46a of the front and rear engaging rollers 47 and 46.
Further, the engaging projection 48a of the intermediate engaging
roller 48 contacts the engaging recess 46a of the rear engaging
roller 46 to thereby press the rear engaging roller 47 against the
portion of the splitter 20 defining the rear end of the second slot
20b and to press the front engaging roller 47 against the portion
of the splitter 20 defining the front end of the second slot 20b by
a reaction force. As the front and rear engaging rollers 47 and 46
are pressed against the portions of the splitter 20 defining the
front and rear ends of the second slot 20b, the engaging recesses
47a and 46a of the front and rear engaging rollers 47 and 46 are
reliably held to be engaged with the portions of the splitter 20
defining the front and rear ends of the second slot 20b. Therefore,
the front and rear engaging rollers 47 and 46 are reliably held in
position relative to the splitter 20 with respect to the direction
parallel to the surface of the splitter 20 and also with respect to
the direction substantially perpendicular to the surface of the
splitter 20. This may reliably hold the mounted state of the mount
frame 30 and eventually the mounted state of the guard device 50
and the kickback preventing claw members 60 to the splitter 20.
[0060] In order to remove the mount mechanism 40 from the splitter
20, the operator may pivot the lever 41 upward to move the rear
engaging roller 46 toward the front engaging roller 47 until the
distance between the front side portion of the front engaging
roller 47 and the rear side portion of the rear engaging roller 46
becomes smaller than the width L1. Then, the front and rear
engaging rollers 47 and 46 can be moved from the second slot 20b to
the first slot 20a and further to the outside of the splitter 20.
Therefore, the mount mechanism 40 can be removed from the splitter
20. Removing the mount mechanism 40 from the splitter 20 can also
result in the removal of the mount frame 30, guard device 50 and
the kickback preventing claw members 60 from the splitter 20.
[0061] In this way, the mount mechanism 40 enables the mount frame
30, the guard device 50 and the kickback preventing claw members 60
to be reliably mounted to and removed from the splitter 20 by a
simple vertical pivoting operation of the lever 41.
[0062] As shown in FIG. 11, two bushes 49 are rotatably supported
on the fixed shaft 42 of the mount mechanism 40. The front engaging
roller 47 is positioned between these two bushes 49. Thus, the
kickback preventing claw members 60 can be vertically pivotally
supported by the fixed shaft 42 via the respective bushes 49.
Torsion springs 62 are fitted on the respective bushes 49. One end
of each torsion spring 62 engages the top part 30a of the mount
frame 30 and the other end of each torsion spring 62 engages the
corresponding kickback preventing claw member 60 from its upper
side. Therefore, the torsion springs 62 serve to normally urge the
kickback preventing claw members 60 downward.
[0063] The kickback preventing claw members 60 can be disposed on
laterally opposite sides of the saw blade 3 and each can include
claws 60a at its lower side as shown in FIG. 12 for engaging the
workpiece W. With the workpiece W pressed downward against the
surface of the table 2 by the claws 60a of the kickback preventing
claw members 60, the workpiece W may be prevented from being
accidentally lifted due to the kickback phenomenon that may be
caused by the force applied to the workpiece W by the rotating saw
blade 3. Claws 60a can include other configurations as long as it
provides favorable interaction with the workpiece W.
[0064] As described previously, the left and right protection arms
30e and 30f extend forwardly from the left and right side parts 30b
and 30c of the inverted U-shaped portion 30U of the mount frame 30.
As shown in FIG. 3, two claw holding springs 61 can be mounted
between the front ends of the protection arms 30e and 30f.
[0065] By engaging the front ends of the kickback preventing claw
members 60 with the claw holding springs 61 after pivoting the
kickback preventing claw members 60 upward against the biasing
forces of the torsion springs 62, it is possible to hold the
kickback preventing claw members 60 at an upward rest position. At
the rest position, the kickback preventing claw members 60 are
positioned to extend substantially along the respective protection
arms 30e and 30f. Therefore, the laterally outer sides of the
kickback preventing claw members 60 can be covered by the
respective protection arms 30e and 30f, so that other structural
members can be reliably prevented from accidental interference with
the kickback preventing claw members 60.
[0066] As described previously, the splitter 20 can be mounted on
the base portion 5a of the lift base 5 via the mount base 25. The
base portion 5a extends forwardly from the lift base 5 as shown in
FIG. 1. The details of the mount base 25 are shown in FIGS. 13 and
14. The mount base 25 can include a fixed base 21 and a clamp plate
22. The fixed base 21 is fixedly mounted on the base portion 5a of
the lift base 5 via bolts 21a. The clamp plate 22 is adapted to
clamp the lower portion of the splitter 20 in the direction of its
thickness against the fixed base 21.
[0067] Upper and lower support shafts 23 extend between the fixed
base 21 and the clamp plate 22. The support shafts 23 have stepped
portions for engaging the clamp plate 22. Nuts 23b engage with the
support shafts 23 from the side opposite to the stepped portions
with respect to the clamp plate 22, so that the support shafts 23
are fixed in position by the tightening forces applied to the nuts
23b. Compression springs 24 are interposed between heads 23a of the
support shafts 23 and the fixed base 21, so that the compression
springs 24 bias the clamp plate 22 in a direction toward the fixed
base 21 or the direction for clamping the splitter 20. A fixing
screw 29 fixes one of the support shafts 23 in position relative to
the clamp plate 22, so that the clamp plate 22 can be fixed in
position relative to the fixed base 21.
[0068] As shown in FIGS. 12 to 14, an elongated mount slot 20c can
be formed in the lower portion of the splitter 20 and is opened at
the lower edge of the splitter 20. Preferably, the mount slot 20c
extends along an arc about the rotational axis of the saw blade 3.
The support shafts 23 are inserted into the mount slot 20c.
[0069] As shown in FIG. 13, a plurality of substantially
semicircular recesses 20d can be formed in the front edge of the
splitter 20. Two semicircular recesses 20d can be included in this
embodiment. The fixed base 21 has a fixing shaft 27 that extends
throughout the thickness of the fixed base 21. A compression spring
26 is interposed between a head 27a of the fixing shaft 27 and the
fixed base 21 in order to bias the fixing shaft 27 in the right
direction as viewed in FIG. 14. A fixing block 28 having a
substantially truncated conical configuration is attached to the
left end of the fixing shaft 27 and is engageable with any one of
the semicircular recesses 20d in order to fix the splitter 20 in
position relative to the mount base 25 through cooperation with the
support shafts 23.
[0070] The clearance between the clamp plate 22 and the fixed base
21 can be adjusted by the following process. First, the fixing
screw 29 is loosened; so that the clamp plate 22 is biased toward
the fixed base 21 by the compression springs 24. The clamp plate 22
therefore contacts with the fixed base 21. Then, the splitter 20 is
inserted between the clamp plate 22 and the fixed base 21 from the
upper side. In order to facilitate the inserting operation, an
upper corner portion 21a of the fixed base 21 and an upper corner
portion 22a of the clamp plate 22, which can be oppose to each
other, are chamfered. Therefore, so that the splitter 20 can be
wedged between the fixed base 21 and the clamp plate 22 under the
guide of the chamfered upper corner portions 21a and 22a. As a
result, the fixed base 21 and the clamp plate 22 can be spaced from
each other by the distance corresponding to the thickness of the
splitter 20. Then, the fixing screw 29 is tightened to fix the
clamp plate 22 in position relative to the fixed base 21, so that
the clearance between the fixed base 21 and the clamp plate 22 may
be maintained. In this state, the support shaft 23 that is disposed
on the lower side as viewed in FIG. 14 is not fixed in position
relative to the fixed base 21. However, the compression spring 24
associated with the lower support shaft 23 does not act to move the
clamp plate 22, because the fixed base 21 and the clamp plate 22
are fixed in position by the fixing screw 29 associated with the
upper support shaft 23.
[0071] Because the clearance between the clamp plate 22 and the
fixed base 21 can be set and fixed to correspond to the thickness
of the splitter 20 to be used, potential movement in the direction
of thickness of the splitter 20 is reduced while the adjustment of
vertical position of the splitter 20 along the mount slot 20c may
be possible. The same setting process can be applied to different
splitters having different thicknesses.
[0072] In order to set the splitter 20, the operator can insert the
lower portion of the splitter 20 into the clearance between the
clamp plate 22 and the fixed base 21 such that the support shafts
23 enter the mount slot 20c. When the splitter 20 has been moved in
such a position that any one of the fixing recess 20d of the
splitter 20 opposes the fixing block 28 of the fixing shaft 27, the
fixing block 28 can engage with the fixing recess 20d due to the
biasing force of the compression spring 26. As a result, the
splitter 20 can be fixed in position with respect to both the
direction perpendicular to the thickness of the splitter 20 and the
direction parallel to the surface of the splitter 20.
[0073] In order to change the vertical position of the splitter 20,
the operator may push the head 27a of the fixing shaft 27 against
the biasing force of the compression spring 26, so that the fixing
block 28 may be disengaged from the fixing recess 20d. Then, the
operator vertically moves the splitter 20 to a position where the
fixing block 28 opposes to another fixing recess 20d. This movement
can be easily made, because no substantial clamping force is
applied to the splitter 20. Thereafter, the operator may release
the pushing force applied to the fixing shaft 27, so that the
fixing block 28 engages the fixing recess 20d by the biasing force
of the spring 26. As a result, the splitter 20 can be again fixed
in position with respect to both the direction perpendicular to the
thickness of the splitter 20 and the direction parallel to the
surface of the splitter 20.
[0074] In order to remove the splitter 20, the operator also can
push the head 27a of the fixing shaft 27 for disengaging the fixing
block 28 from the fixing recess 20d. Then, the operator may simply
lift the splitter 20 for disengaging the mount slot 20c from the
support shafts 23.
[0075] According to the one embodiment of the present invention as
described above, the mount flame 30 can be removed from the upper
portion of the splitter 20 by upwardly pivoting the lever 41 of the
mount mechanism 40. Because the guard device 50 and the kickback
preventing claw members 60 are mounted to the mount frame 30, the
guard device 50 and the kickback preventing claw members 60 can be
removed from the splitter 20 together with the mount frame 30 by
simply pivoting the lever 41. Therefore, the difficulty in removing
the mount frame 30, the guard device 50 and the kickback preventing
claw members 60 can be considerably reduced in comparison with the
operations for removing these elements from the splitter 20
separately from each other.
[0076] In addition, mounting the mount frame 30 to the splitter 20
also attaches the guard device 50 and the kickback preventing claw
members 60 to the splitter 20. Therefore, the difficulty in
mounting the mount frame 30, the guard device 50 and the kickback
preventing claw members 60 can be considerably reduced in
comparison with the operations for mounting these elements to the
splitter 20 separately from each other.
[0077] Further, downwardly pressing the operation lever portion 51a
may enable the mount holder 51 to be removed from the tubular
portion 30T of the mount frame 30 and to eventually remove the
guard device 50 from the mount frame 30. Therefore, it is possible
to remove the guard device 50 from the splitter 20 while the
kickback preventing claw members 60 being held to be mounted to the
splitter 20. This may improve the operability in removing the saw
blade 3 and in performing the maintenance work. On the contrary,
inserting the mount holder 51 into the tubular portion 30T of the
mount frame 30 can mount the guard device 50 to the mount frame 30.
Therefore, the guard device 50 can be easily mounted to the
splitter 20. The operability in performing maintenance work on the
cutting device 1 can be improved.
[0078] Furthermore, because the mount frame 30 can be mounted to
and removed from the splitter 20 by simply vertically pivoting the
lever 41 of the mount mechanism 40, the guard device 50 and the
kickback preventing claw members 60 can be easily mounted to and
removed from the splitter 20 without utilizing special tools.
[0079] Still furthermore, the mount base 25 can be used for
mounting various splitters having different thicknesses to the lift
base 5. Additionally, the splitter 20 can be removed by simply
pushing the fixing shaft 27 of the mount base 25. Therefore, it is
possible to replace the splitter 20 to change the vertical position
of the splitter 20 without using special tools.
[0080] Furthermore, the kickback preventing claw members 60 can be
held in the upper rest position by the claw holding springs 61. The
kickback preventing claw members 60 can be returned from the rest
position to the kickback preventing position by downwardly pivoting
the kickback preventing claw members 60 after disengaging from the
claw holding springs 61. Therefore, the operability of the kickback
preventing claw members 60 can be further improved.
[0081] In the rest position, the kickback preventing claw members
60 extend between and along the protection arms 30. Therefore, it
is possible to reliably prevent the other articles, such as
hand-held tools, from being interfered by the kickback preventing
claw members 60.
[0082] The above embodiments may be modified in various ways. For
example, when the mount holder 51 is inserted into the tubular
portion 30T of the mount frame 30, the removal preventing stop 51b
engages the stop hole 30g, so that the mount holder 51 is held in
the mounted position, and eventually, the guard device 50 can be
mounted to the mount frame 30. However, screws may be used for
removably attaching the mount holder 51 to the tubular portion 30T
of the mount frame 30. In such a case, the lever 51a and the
removal preventing stop 51b may be omitted.
[0083] Additionally, the mount holder 51, the guard frame 52 and
the guard holder 53 may be formed integrally with each other. One
example to accomplish this is by using a molding process including
synthetic resin
[0084] Although the tubular portion 30T of the mount frame 30 has a
rectangular cross section in the above embodiments, the tubular
portion 30T may have different cross sectional configurations, such
as circular and triangular cross sections. In addition, the tubular
portion 30T may be replaced with a non-tubular portion, if the
mount holder 51 is removably attached to the tubular portion 30T by
screws as noted previously.
[0085] The mount mechanism 40 may be replaced with any other mount
mechanisms. For example, the mount frame 30 may be removably
mounted to the upper proton of the splitter 20 by using bolts that
clamp the splitter 20 from opposite sides with respect to the
thickness direction. In such a case, the first and second slots 20a
and 20b of the splitter 20 can be eliminated.
[0086] Further, although the mount base 25 is configured to enable
the splitter 20 to be mounted and removed by the pushing and
releasing operations of the fixing shaft 27, this mounting
construction can be replaced with different constructions. For
example, the splitter 20 may be clamped between the clamp plate 22
and the fixed base 21 by means of bolts. In such a case, the
support shafts 23, the fixing shaft 27 and their associated parts
can be eliminated.
* * * * *