Portable saws having chip scattering prevention devices

Details Portable saws having chip scattering prevention devices Portable saws having chip scattering prevention devices

1999-07-23

2001-08-07

Watts, Douglas D. (Department: 3724)

Cutlery

Cutting tools

Saw

C030S390000

Reexamination Certificate

active

06269543

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to portable saws having a device that prevent chips generated by a cutting operation from scattering to the surrounding area.
2. Description of the Related Art
A known portable saw having a device for preventing cutting chips from scattering is taught in Japanese Utility Model Publication No. 6-47683. For explanation purposes,
FIG. 2
from this Japanese Utility Model Publication has been reproduced as
FIG. 8
in this application. As shown in
FIG. 8
, the known portable saw consists of a bifurcated chip cover
52
that has a pair of lateral walls
52
a
and a front wall
52
b
so as to cover both lateral sides and the front side of a cutting chip exhaust area, which area is normally defined as a position adjacent to a base
53
on the front side (right side as viewed in
FIG. 8
) of a saw blade
51
. The base
53
is adapted to be placed on a workpiece and the saw blade
51
can be moved to partly extend through the base
53
to cut the workpiece. The chip cover
52
may prevent the cutting chips of the workpiece from being exhausted either forwardly or laterally. Instead, the cutting chips are intended to be swept upwardly in the rotational direction of the saw blade
52
(as indicated by an arrow in
FIG. 8
) so as to be collected in a chip collector (not shown).
The chip cover
52
is mounted so as to pivot vertically on a bracket
53
a
by means of a pin
54
. The bracket
53
a
is fixed to the upper surface of the base
53
. A torsion spring
55
serves to normally bias the chip cover
52
to contact the upper surface of the base
53
. The saw blade
51
is rotatably mounted on a saw unit
56
that also is mounted so as to vertically pivot around the bracket
53
a
by means of a pin
57
. A motor (not shown) drives the saw blade
51
.
As the saw unit
56
pivots upward relative to the base
53
, the blade profile below is reduced, so that the cutting depth of the saw blade
51
into the workpiece is reduced. Because the chip cover
52
is biased by the torsion spring
55
to contact the base
53
, both lateral sides of the cutting chip exhaust area are covered by the lateral walls
52
a
of the slide cover
52
.
However, because the saw blade
51
separates from the front wall
52
b
of the chip cover
52
as the saw unit
56
pivots upward, the space between the saw blade
51
and the front wall
52
b
increases. In other words, the front wall
52
b
moves away from the cutting chip exhaust area. As a result, the known slide cover may not effectively prevent the cutting chips from scattering to the surrounding area.
SUMMARY OF THE INVENTION
It is, accordingly, one object of the present invention to teach improved portable saws having a device that serves to effectively prevent cutting chips from scattering to the surrounding area.
Preferably, a portable saw is taught that includes a chip cover and an associated control device. The chip cover can prevent cutting chips from scattering to the surrounding area and preferably pivots about an axis that is the same as the rotational axis of the saw blade.
If the chip cover pivots about the same axis as the saw blade, the positional relationship in the diametrical direction between the chip cover and the saw blade does not change, regardless of changes in the chip cover position. In addition, the control device taught herein may bc utilized to suitably position the chip cover to cover the cutting chip exhaust area, which area may be defined as a position adjacent to the outer peripheral portion of the saw blade and adjacent to a base that is designed to contact or rest on a workpiece. As a result, the cover may effectively prevent the cutting chips from scattering to the surrounding area, regardless of changes in the vertical position of the saw unit relative to the base or changes in the saw blade cutting depth.
In one representative embodiment, the chip cover may have a cover portion that is spaced from an outer periphery of the saw blade by a predetermined distance and that may extend substantially along an arc about the pivotal axis. Preferably, the cover has a plate-like shape and has the cover portion at its distal end opposite to the pivotal axis.
The control device may include a cam mechanism that is provided between the chip cover and the base. Preferably, the cam mechanism includes a cam pin and a cam recess that are provided on the cover and the base, respectively.
Other objects, features and advantages of the present invention will be readily understood after reading the following detailed description together with the accompanying drawings and the claims.


REFERENCES:
patent: 4856394 (1989-08-01), Clowers
patent: 6-47683 (1989-02-01), None

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