Note: Descriptions are shown in the official language in which they were submitted.
CA 02471606 2004-06-10
SAWING ~IRECTION POSITIONING SYS'T'EM FOR A JIGSAW
Field of the Invention
s The present invention relates to a positioning system, and more
particularly, to a
sawing direction positioning system for a jigsaw.
Description of the Backgiround Art
to A jigsaw is a woodworking machine that saws curvly a wood. When a
conventional
jigsaw is used to saw a wood, a curve line that corresponds to the final shape
of
the wood to be sawed is drawn on the wood beforehand and the wood to be
sawed is then pushed and adjusted manually so that: a saw blade of the jigsaw
always saws the wood tangentially to the curve line drawn on the wood during
Is working. During sawing, one operator should keep his eyes on the position
of the
wood to ensure that the sawing direction is correci: or keeps in line with the
tangential line of the drawn curve line, thereby preventing the kerf from
offsetting.
However, other things such as sawdust may obstruct the operator's sight line
so
that it is difficult for the operator to control the sawing, thereby resulting
in many
2o rejected products.
Summar~r of the Invention
An object of the invention is to overcome the defects and problems in the
prior art
2s and provide a sawing direction positioning system for a jigsaw.
To achieve the object of the invention, there is provided a sawing direction
positioning system for a jigsaw comprising a light-emitting unit for emitting
a planar
light beam, said light-emitting unit being connected with a power supply via a
lead
3o and positioned above said jigsaw so that said planar light beam emitted
from the
light-emitting unit coincides exactly with the plane of a saw blade mounted on
said
jigsaw.
The sawing direction positioning system for a jigsaw accarding to the present
3s invention is simple and low-cost. During sawing, adjustment may be made
easily
so that the wood to be sawed is positioned rapidly and accurately along a
correct
sawing direction. It can be used widely in various jigsaws.
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CA 02471606 2004-06-10
Brief Description of the Drawincts
Fig 1 is a schematic view showing a jigsaw provided with a sawing direction
positioning system according to the present invention.
s Fig 2 is a schematic view showing a jigsaw provided with a sawing direction
positioning system according to another embodiment of the present invention.
Fig 3 is a schematic view showing the installation of the sawing direction
positioning system according to the present invention.
Fig 4 is a schematic diagram showing the light-emitting unit according to the
to present invention.
Detailed Description of the Preferred Embodiment:
As shown in Fig 1, a sawing direction positioning system for a jigsaw
according to
Is the present invention includes one light-emitting unit 3 for emitting a
planar light
beam 6. The light-emitting unit 3 is positioned above the jigsaw so that the
planar
light beam 6 emitted from the light-emitting unit 3 coincides exactly with the
plane
of a saw blade 5 mounted on the jigsaw. Preferably, the light-emitting unit 3
is
positioned at a fixing seat 2 provided on an upper housing 1 of the jigsaw.
The
20 light-emitting unit 3 is connected with a power supply via a lead 4. The
projection
line of the planar light beam 6 on a wood to be sawed, i.e. the intersecting
line of
the planar light beam 6 and the wood is a very fine straight line. In the
embodiment as shown in Fig 1, the fixing seat 2 is formed integrally with the
upper
housing 7 of the jigsaw.
2s
Preferably, the light-emitting unit 3 for emitting the planar light beam 6 is
pen-
shaped.
Fig 2 shows a sawing direction positioning system according to another
3o embodiment of the present invention. This sawing direction positioning
system is
substantially similar to that shown in Fig 1 except for the fixing seat 2. in
this
embodiment shown in Fig 2, the fixing seat 2 is a cantilever extending from
the
upper housing 1 of the jigsaw. The light-emitting unit 3 is mounted adjustably
at
the front end of the cantilever.
3s
As shown in Fig 3, a hole 9 for receiving the light-emitting unit 3 is formed
on the
fixing seat 2. The light-emitting unit 3 is installed in the hole 9 of the
f<xing seat 2.
At the top end of the fight-emitting unit 3 opposite to the emitting end are
formed
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CA 02471606 2004-06-10
female or male threads 10. A regulatory screw 12 with corresponding male or
female threads and a shoulder 11 engages with the female or male threads 10.
The regulatory screw 12 and the light-emitting unit 3 are clamped on a
shoulder 8
provided at the fixing seat 2 by means of the threads. By loosening the
regulatory
s screw 12, the position of the light-emitting unit 3 may be adjusted
circumferentially,
thus adjusting the direction and position of the planar light beam 6. Of
course,
adjusting the fixing seat 2 relative to the upper hausing 1 of the jigsaw also
changes the direction and position of the planar light beam 6.
to Fig 3 shows the light-emitting unit 3 according to the present invention in
detail. In
the present preferred embodiment, the light-emitting unit 3 according to the
present invention includes a light source, a converging lens 14 disposed
coaxially
in front of the light source and a cylindrical lens 15 eiisposed coaxially in
front of
the converging lens 14. The light emitted from the light source is converged
by
is the converging lens 14 and the passes through the cylindrical lens 15 to
form the
planar light beam 6. Of course, a corrugated lens may be used instead of the
cylindrical lens.
As shown in Fig 4, a laser diode 13 may be used as the light source. Usually,
the
20 laser diode is of high power and emits bright light that may injure the
operator's
eyes. Further, the laser diode generally emits only red light so that it is
difficult to
meet the requirements for colours in different applications.
Preferably, a light emitting diode 7 as shown in Fig 3 is used as the light
source.
2s The light emitting diode may emit lights of various colours that do not
injure the
operator's eyes. For example, the light emitting diode may emit lights such as
white, blue, red, green and yellow to meet the requirements in different
applications. Compared with a laser diode, a light emitting diode is more cost-
effective. The light emitting diode 7 may be a monochromatic light emitting
diode,
3o a two-color sight emitting diode or a RGB light emitting diode. If a two-
color light
emitting diode or a RGB light emitting diode is used, they may also emit a
monochromatic light as required by means of a control circuit.
As shown in Figs 1-3, at mounting a sawing direction positioning system for a
3s jigsaw according to the present invention, the center lines of the fixing
seat 2 and
the fight-emitting unit 3 coincide exactly with the plane of the saw blade 5
by
adjusting the axing seat 2 relative to the upper housing 1 of the jigsaw. When
the
light-emitting unit 3 is switched on, the planar light beam 6 emitted from the
light-
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CA 02471606 2004-06-10
emitting unit 3 projects a very fine straight projection line on the wood to
be sawed.
During sawing, the projection line always keeps tangential to the curve line
drawn
on the wood by adjusting manually the wood and the saw blade 5 always saws the
wood along the projection line. Thus, a desirable kerF is worked. To ensure
that
s the projection line is clear and visible, it is possible to choose an
appropriate light
such as white, blue and red that considerably contrasts with the wood to be
sawed.
By loosening the regulatory screw, the light-emitting unit 3 may rotate on the
fixing
seat until the projection line of the planar light beam emitted from the light-
emitting
io unit 3 coincides precisely with the plane of the saw blade 5. The fight-
emitting unit
3 is then kept in position by hand while the regulatory screw 6 is tightened.
During sawing, the projection line of the planar light beam emitted from the
fight-
emitting unit 3 always projects on the wood to be sawed and is not obstructed
by
is the sawdust at all. The operator may have a good visual field and push the
wood
to be sawed along the curve line to ensure that the projection line always
keeps
tangential to the curve line drawn on the wood and the saw blade always saws
the
wood along the projection line, thereby preventing the kerf from offsetting
and
reducing the rejected products.
Having described the invention in detail, those skilled in the art will
appreciate that
modifications of this invention may be made without departing from its spirit.
Therefore, it is not intended to limit the present invE:ntion only to the
preferred
embodiments illustrated and described. Rather, the scope of the invention is
to be
2s determined by the appended claims and their equivalents.
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