CUT FINISH ACTUATOR FOR TABLE SAW

ACTIONNEUR DE FINITION DE COUPE POUR TABLE DE SCIAGE

English Abstract

A table saw having an actuator to stop rotation of the cutting blade when the cutting operation for the material being cut is complete. The actuator is located adjacent the cutting blade near the midpoint of the opening through which the cutting blade extends.

French Abstract

Une table de sciage comprenant un actionneur permettant d'arrêter la rotation de la lame de coupe si l'opération de coupe du matériau à couper est terminée. L'actionneur est situé à proximité de la lame de coupe près du milieu de l'ouverture dans laquelle la lame de coupe se prolonge.

Claims

CLAIMS
1. A table saw comprising:
a top surface with an opening having a first end and a second end to define a
longitudinal length;
a rotatable blade extending through the opening and configured for cutting a
material
having a leading edge and a trailing edge with respect to movement of the
material past the
rotatable blade; and
an actuator located adjacent the opening near a midpoint of the longitudinal
length of
the opening and operable to stop rotation of the rotatable blade in response
to detecting the
trailing edge of the material.
2. The table saw of claim 1 further comprising a motor to drive the rotatable
blade.
3. The table saw of claim 2 wherein the actuator when actuated stops power to
the
motor.
4. The table saw of claim 1 wherein detection of the trailing edge of the
material by the
actuator occurs after the cutting operation of the material is complete.
5. The table saw of claim 1 wherein the actuator is located closer to the
second end of
the opening than the first end.
6. The table saw of claim 1 wherein the actuator is a contact switch biased
toward a
position in which the switch extends above the top surface.
7. The table saw of claim 6 wherein the leading edge of the material depresses
the
switch to initialize the switch, and wherein the switch resumes its biased
position after the
trailing edge of the material moves past the switch.
8. The table saw of claim 7, wherein the switch stops rotation of the
rotatable blade
when the switch resumes its biased position.

Description

CA 02638048 2010-05-11
CUT FINISH ACTUATOR FOR TABLE SAW
[0001] The present invention relates to an actuator for a table saw that stops
rotation of the cutting blade and in particular to an actuator that stops
rotation of the
cutting blade when the cutting operation for material that is being cut is
finished. The
invention is suitable for all manner of cutting operations including through
cuts and non-
through cuts.
SUMMARY
[0002] The present invention provides a table saw with a top surface having an
opening through which a cutting blade extends. The opening has a longitudinal
length
greater than the diameter of the cutting blade to provide clearance for the
cutting blade.
The table saw also has an actuator located adjacent at least one side of the
opening
near the midpoint of the longitudinal length of the opening. The actuator
functions to
stop rotation of the blade when actuated. The actuator will be actuated when
the
desired cutting operation for the material being cut is complete. It will be
appreciated
that by locating the actuator near the midpoint of the longitudinal length of
the opening,
the cutting operation for the material being cut will have been completed at
that time.
The rotation of the blade may occur by stopping power to the motor which
drives the
blade, by providing a clutch operatively associated with the motor and blade
such that
the clutch will allow the motor to run yet prevent the blade from rotating, by
providing a
brake to stop rotation of the blade, combinations of the above and other known
structures for stopping the rotation of the blade.
[0003] According to one aspect of the present invention there is provided a
table
saw comprising a top surface with an opening having a first end and a second
end to
define a longitudinal length; a rotatable blade extending through the opening
and
configured for cutting a material having a leading edge and a trailing edge
with respect
to movement of the material past the rotatable blade; and an actuator located
adjacent
the opening near a midpoint of the longitudinal length of the opening and
operable to
stop rotation of the rotatable blade in response to detecting the trailing
edge of the
material.
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CA 02638048 2010-05-11
[0004] In one aspect, the actuator includes a biased switch that can be
depressed
when the material that is being cut comes into contact with the switch.
Depression of
the switch will initialize a circuit so that when there is no material
operating against the
bias of the switch, the switch will be biased away from the surface of the
table saw and
stop rotation of the cutting blade. In this aspect, it will be understood that
the switch is
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CA 02638048 2008-07-17
normally biased away from the top surface of the table saw. The actuator may
include a
laser, an infra-red source, a photocell, or other type of switch such that
when the switch
is actuated the cutting blade is stopped from rotation.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] Fig. 1 shows a perspective view of a representative table saw
incorporating the cut finish actuator of the present invention.
[0006] Fig. 2 is a side of the table saw of Fig. 1 with a portion of the side
being cut
away to illustrate the motor.
[0007] Fig. 3 is a top view of the table saw of Fig. 1 with the blade removed
to
better illustrate certain concepts of the invention.
[0008] Figs. 4-6 show operation of one embodiment of the actuator of the
present
invention with the blade removed to better illustrate the operation. In
particular, Fig. 4
shows the actuator as the material is initially being cut but before it is in
contact with the
actuator. In this aspect, the actuator is in its normally biased position with
the switch
located away from the top surface of the table.
[0009] Fig. 5 shows the actuator as the material is being cut and with the
switch in
a depressed position.
[0010] Fig. 6 shows the actuator when the cutting operation for the material
is
completed and the actuator is biased away from the top surface of the table.
DETAILED DESCRIPTION
[0011] The invention is described with reference to the drawings in which like
elements are referred to by like numerals. The relationship and functioning of
the
various elements of this invention are better understood by the following
description.
Each aspect so defined may be combined with any other aspect or aspects unless
clearly indicated to the contrary. The embodiments described below are by way
of
example only, and the invention is not limited to the embodiments illustrated
in the
drawings.
[0012] Turning now to Fig. 1, a table saw 10 having the cut finish actuator of
the
present invention is shown. The table saw 10 can be of any known type such as
a
stand-alone table saw or a portable table saw. The table saw shown in Fig. 1
is
designed to be moved. The table saw 10 includes a top or cutting surface 12.
The top
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CA 02638048 2008-07-17
or cutting surface 12 includes an opening 30 through which a blade 16 extends.
In
general, as better seen in Fig. 2, the blade is rotated by a motor 18 located
below the
top surface 12. The blade 16 is used to cut material 20 such as wood that is
pushed
along the top or cutting surface 12 and moved into contact with the blade 16.
[0013] The opening 30 has a first side 32 and a second side 34 to define a
width
W and a. first end 36 and a second end 38 to define a longitudinal length L.
The first end
36 is associated with the beginning of the material 20 to be cut. In other
words, the saw
blade 16 rotates in a direction toward the first end 36 of the opening 30.
[0014] At least one actuator 40 is located adjacent the opening 30 at or near
the
mid point of the longitudinal length L of the opening 30. It is contemplated
to provide an
actuator 40 adjacent at least one side of the opening 30 near the mid point of
the
longitudinal length L of the opening 30. In one aspect, the at least one
actuator 40 is
located within about 10% of the distance from the midpoint of the longitudinal
length L.
For example, if the longitudinal length is 20 mm, the midpoint would be 10 mm
and the
actuator could be located within about 9 to about 11 mm from the first end 36
of the
opening 30. In another aspect, the actuator 40 is provided at the mid point of
the
longitudinal length. Desirably, the actuator is provided after the mid point.
The term
"after" means that the actuator is closer to the second end 38 of the opening
than the
first end 36 of the opening.
[0015] The actuator 40 functions to stop rotation of the blade 16 when
actuated.
The actuator 40 will be actuated when the cutting operation for the material
20 being cut
is complete. It will be appreciated that by locating the actuator 40 near the
midpoint of
the longitudinal length L of the opening 30, the cutting operation for the
material 20
being cut will have been completed.
[0016] The rotation of the blade 16 may occur by stopping power to the motor
18
which drives the blade 16 or by providing a clutch operatively associated with
the motor
18 and blade 16 such that the clutch will allow the motor 18 to run yet
prevent the blade
16 from rotating. The rotation of the blade 16 may also occur by providing a
brake to
physically stop rotation of the blade 16. Of course, it is contemplated that
each of the
above structures for stopping rotation of the blade 16 may be used in
combination with
each other.
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CA 02638048 2008-07-17
[0017] In one aspect, the actuator 40 includes a biased switch that can be
actuated in the following manner. As seen in Fig. 4, the switch is normally
biased in a
position such that it extends from the top surface 12 of the table saw 10. As
the cutting
of the material 20 begins, the switch is depressed to initialize the switch as
shown in Fig.
5. Subsequently, as the cutting operation is completed and the material. moves
past the
switch, the switch is again biased away from the top surface as shown in Fig.
6, causing
the rotation of the blade to stop. One of skill in the art can appreciate that
the actuator
40 described above will operate during a variety of cutting operations such as
a through
cut, a non-through cut, and the actuator 40 and its operation are not limited
by the type
of cut being performed.
[0018] While Figs. 4-6 shown one form of an actuator 40, it is contemplated
that
the actuator may include a laser, an infra-red source, a photocell, or other
type of switch
such that when the cutting operation for the material being cut is completed,
the switch
is actuated causing the cutting blade to stop rotating.
[0019] The foregoing detailed description has described only a few of the many
forms that this invention can take. For this reason, this detailed description
is intended
by way of illustration, and not by way of limitation. It is only the following
claims,
including all equivalents that are intended to define the scope of this
invention.
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Representative Drawing