U.S. patent application number 11/865956 was filed with the patent office on 2008-01-24 for system and method for rapidly stopping a spinning table saw blade.
Invention is credited to David V. Keller.
Application Number | 20080016998 11/865956 |
Document ID | / |
Family ID | 36314980 |
Filed Date | 2008-01-24 |
United States Patent
Application |
20080016998 |
Kind Code |
A1 |
Keller; David V. |
January 24, 2008 |
System and Method for Rapidly Stopping a Spinning Table Saw
Blade
Abstract
A system for stopping a spinning table saw blade is comprised of
a pin assembly disposed adjacent to a saw blade assembly for
stopping a spinning saw blade. A receiving block is disposed on a
side of the saw blade opposing the pin assembly for receiving the
tip of the pin assembly. A driving assembly is coupled to the pin
assembly for driving the pin assembly into the spinning saw blade
into the receiving block. Finally, a sensing assembly is coupled to
at least one of the saw blade assembly and the driving assembly for
sensing encroachment of a user's hand in a pre-defined zone. In
use, upon sensing a user's hand the sensing assembly signals the
driving assembly to stop the spinning saw blade by driving the pin
assembly through the saw blade and into the receiving block.
Inventors: |
Keller; David V.; (Jackson,
TN) |
Correspondence
Address: |
THE BLACK & DECKER CORPORATION
701 EAST JOPPA ROAD, TW199
TOWSON
MD
21286
US
|
Family ID: |
36314980 |
Appl. No.: |
11/865956 |
Filed: |
October 2, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11025356 |
Dec 29, 2004 |
7290474 |
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11865956 |
Oct 2, 2007 |
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10836132 |
Apr 29, 2004 |
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11025356 |
Dec 29, 2004 |
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60466199 |
Apr 29, 2003 |
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60533192 |
Dec 30, 2003 |
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Current U.S.
Class: |
83/13 ;
83/58 |
Current CPC
Class: |
F16P 3/144 20130101;
Y10T 83/04 20150401; Y10T 83/773 20150401; F16P 3/142 20130101;
B27G 19/02 20130101; B27B 5/38 20130101; F16P 3/148 20130101; Y10T
83/081 20150401; Y10S 83/01 20130101; Y10T 83/8863 20150401; B23D
59/001 20130101 |
Class at
Publication: |
083/013 ;
083/058 |
International
Class: |
B26D 5/00 20060101
B26D005/00; B23D 59/00 20060101 B23D059/00; B27B 5/38 20060101
B27B005/38 |
Claims
1. A system for stopping a spinning saw blade, comprising: a pin
assembly disposed adjacent to a saw blade assembly for stopping the
spinning saw blade, the pin assembly including a first end, the
first end including a pointed tip for piercing the saw blade; a
receiving block disposed on a side of the saw blade opposing the
pin assembly for receiving the tip of the pin assembly; a driving
assembly coupled to the pin assembly for driving the pin assembly
into the spinning saw blade and into the receiving block; and a
sensing assembly coupled to at least one of the saw blade assembly
and the driving assembly for sensing encroachment of a user's hand
in a pre-defined zone, wherein upon sensing a user's hand the
sensing assembly signals the driving assembly to stop the spinning
saw blade by driving the pin assembly through the saw blade and
into the receiving block.
2. The detection system of claim 1, wherein the sensing system
comprises a video proximity device.
3. The system for stopping a spinning saw blade of claim 1, wherein
the sensing assembly comprises a laser device.
4. The system for stopping a spinning saw blade of claim 1, wherein
the sensing assembly comprises a sensor for detecting the
difference between the electrical capacitance of a user's hand and
a workpiece.
5. The system for stopping a spinning saw blade of claim 1, wherein
the sensing assembly comprises a sensor for detecting the
difference between the electrical resistance of a user's hand and a
workpiece.
6. The system for stopping a spinning saw blade of claim 1, wherein
the sensing assembly recognizes the differences between the shapes
of human body parts and a workpiece.
7. The system for stopping a spinning saw blade of claim 1, wherein
the pin assembly is actuated by a pyrotechnic device.
8. The system for stopping a spinning saw blade of claim 6, wherein
the pyrotechnic device is included within a replaceable
cartridge.
9. The system for stopping a spinning saw blade of claim 1, wherein
the receiving block includes an aperture for receiving the pin
assembly.
10. The system for stopping a spinning saw blade of claim 1,
wherein the pin assembly is formed of hardened steel.
11. A method of stopping a spinning saw blade, comprising:
detecting a user's hand in a pre-defined zone by a detecting
system; and driving a pin assembly through the saw blade into a
receiving block to stop the saw blade from spinning upon detecting
the presence of the user's hand.
12. The method of claim 11, wherein the detecting system comprises
a video proximity device.
13. The method of claim 11, wherein the detecting system comprises
a laser device.
14. The method of claim 11, wherein the detecting system comprises
a sensor for detecting the difference between the electrical
capacitance of a user's hand and a workpiece.
15. The method of claim 11, wherein the detecting system comprises
a sensor for detecting the difference between the electrical
resistance of a user's hand and a workpiece.
16. The method of claim 1, wherein the detecting system recognizes
the difference between the shapes of human body parts and a
workpiece.
17. The method of claim 11, wherein the pin assembly is actuated by
a pyrotechnic device.
18. The method of claim 17, wherein the pyrotechnic device is
included within a replaceable cartridge.
19. The method of claim 11, wherein the receiving block includes an
aperture for receiving the pin assembly.
20. A saw, comprising: a pin assembly disposed adjacent to a saw
blade assembly, the saw blade assembly being configured for
receiving a saw blade, the pin assembly including a first end, the
first end including a pointed tip for piercing the saw blade; a
receiving block disposed on a side of the saw blade opposing the
pin assembly for receiving the tip of the pin assembly; a driving
assembly coupled to the pin assembly for driving the pin assembly
into the saw blade and into the receiving block; and a sensing
assembly coupled to at least one of the saw blade assembly and the
driving assembly for sensing encroachment of a user's hand in a
pre-defined zone, wherein upon sensing a user's hand the sensing
assembly signals the driving assembly to stop the saw blade by
driving the tip of the pin assembly through the saw blade and into
the receiving block.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a continuation-in-part of U.S.
patent application Ser. No. 10/836,132 filed Apr. 29, 2004
(Attorney Docket No. DEL 03-8-2), which in-turn claims priority
under 35 USC .sctn.119(e) to provisional U.S. Application No.
60/466,199 filed Apr. 29, 2003 (Attorney Docket No. DEL 03-8-1). In
addition, the present application claims priority entitled under 35
U.S.C. .sctn.119(e) to provisional U.S. Application No. 60/533,192
filed Dec. 30, 2003 (Attorney Docket No. DEL 03-47-1). Said U.S.
patent application Ser. No. 10/836,132 and U.S. Provisional Patent
Applications Nos. 60/466,199 and 60/533,192 are herein incorporated
by reference in their entirety.
FIELD OF THE INVENTION
[0002] The present invention relates generally to the field of saws
and more particularly to a detection system and method for rapidly
stopping a spinning saw blade.
BACKGROUND OF THE INVENTION
[0003] There exists a need for an effective method to rapidly stop
a spinning saw blade in response to input from a sensing device
that detects possible contact of the blade with a user's hand.
Currently, various methods of stopping a saw blade under such
conditions are available. For example, some methods employ a brake
which makes contact with the blade and causes the blade to drop
below the table surface if the user's hand has made contact with
the saw blade. Additional methods utilize a three-in-one system
including a splitter, anti-kickback fingers and a blade cover.
[0004] All of the presently available systems and methods have one
or more disadvantages in terms of convenience of use, early and
effective detection of a user's hand and cost. For instance, the
system which employs a brake mechanism destroys the saw blade when
used. Further, such system requires contact be made between the
user and the blade prior to activation of the braking mechanism.
Additionally, employment of the three-in-one system severely limits
the flexibility of the machine (e.g. user is limited to making
through-cuts because the splitter sits higher than the blade, any
partial cut such as a groove or a joint may not be done without
removing the entire system).
[0005] Therefore, it would be desirable to design a system and a
method for stopping a rapidly spinning table saw blade overcoming
the aforementioned limitations of inflexibility and required
user/saw blade contact thereby resulting in an efficient, flexible,
early to detect stopping system.
SUMMARY OF THE INVENTION
[0006] In a first aspect of the invention, a system for stopping a
spinning saw blade is disclosed. Such system is comprised of a pin
assembly disposed adjacent to a saw blade assembly for stopping a
spinning saw blade. A receiving block is disposed on a side of the
saw blade assembly opposing the pin assembly for receiving the tip
of the pin assembly. A driving assembly is coupled to the pin
assembly for driving the pin assembly into the spinning saw blade
into the receiving block. Finally, a sensing assembly is coupled to
at least one of the saw blade assembly and the driving assembly for
sensing encroachment of a user's hand in a pre-defined zone. In
use, upon sensing a user's hand the sensing assembly signals the
driving assembly to stop the spinning saw blade by driving the pin
assembly through the saw blade and into the receiving block. In
additional embodiments of the present invention, the sensing
assembly includes shape recognition technology. Further, the pin
assembly is actuated by an explosive substance wherein the
explosive substance is contained within a replaceable
cartridge.
[0007] In a second aspect of the invention, a method for stopping a
rapidly spinning saw blade is disclosed. Such method is comprised
of detecting a user's hand in a pre-defined zone by a detecting
system and driving a pin assembly through the saw blade into a
receiving block to stop the saw blade from spinning upon detecting
the presence of a user's hand.
BRIEF DESCRIPTION OF DRAWINGS
[0008] The numerous advantages of the present invention may be
better understood by those skilled in the art by reference to the
accompanying figures in which:
[0009] FIG. 1 is an isometric view of a table saw including a
sensing assembly in accordance with an exemplary embodiment of the
present invention, wherein the sensing assembly includes a video
proximity device for detecting a user's hand in a pre-defined
zone;
[0010] FIG. 2 is an isometric illustration in accordance with the
video proximity device provided in FIG. 1, wherein the video
proximity device further includes a laser;
[0011] FIG. 3 is an exploded, isometric view of the table saw shown
in FIG. 2, illustrating the indication by a laser beam, visible on
the hand of the operator, that encroachment into a predefined zone
has occurred;
[0012] FIG. 4 is a front view of a table saw in accordance with an
exemplary embodiment of the present invention, wherein the
components of the detection system located beneath the table top of
the table saw are illustrated;
[0013] FIG. 5 is an exploded partial view of the table saw
illustrated in FIG. 4, wherein the pin assembly is retracted;
[0014] FIG. 6 is an exploded partial view of the table saw
illustrated in FIG. 4, wherein the pin assembly has been actuated;
and
[0015] FIG. 7 is flow chart illustrating a method for stopping a
rapidly spinning table saw in accordance with the present
invention.
DETAILED DESCRIPTION OF THE INVENTION
[0016] Reference will now be made in detail to the presently
preferred embodiments of the invention, examples of which are
illustrated in the accompanying drawings.
[0017] Referring in general to FIGS. 1-6, a detection system for
rapidly stopping a spinning saw blade in response to input from a
sensing device that detects possible contact of the blade with a
user's hand is disclosed. In use, upon sensing a user's hand in a
pre-defined zone, a sensing assembly signals a driving assembly to
stop the rapidly spinning saw blade by driving a pin assembly
through the saw blade and into a receiving block. In one
embodiment, the detection system becomes activated prior to a
user's hand making contact with the saw blade which is a major
advantage over the prior art which requires such contact. Further,
the detection system is positioned to allow an workspace on the
table top surface to be unobstructed. In additional embodiments,
the pin assembly is actuated by an explosive or detonation
substance which may be easily replaced after use. As such, the
instant invention overcomes the limitations of partial blade
disintegration, inflexibility and required user/saw blade contact
and thus, yields an efficient, flexible, early to detect stopping
system.
[0018] Referring in general to FIGS. 1-3, an exemplary embodiment
of a sensing assembly included within the instant detection system
is disclosed. The sensing assembly is for sensing encroachment of a
user's hand in a pre-defined zone. In the present embodiment, the
sensing assembly is coupled to the saw blade and the driving
assembly (not shown, see FIGS. 4-6). Further, in the exemplary
embodiment, the sensing assembly is comprised of a video proximity
device. The video proximity device may detect the presence of a
human body part, such as a human hand and the like, in a predefined
zone or point about the working tool element of a power tool.
Moreover, in an exemplary embodiment of the present invention, the
video proximity device is configured to distinguish between a
workpiece, like wood, within the predefined zone or point, and a
human body part. The presence of a body part in the predefined zone
or point is detected through the use of a video camera positioned
for a clear view of the working tool element and the adjacent area.
Should a body part enter this zone or point, the sensing assembly
initiates appropriate countermeasures to prevent contact. For
example, the sensing assembly directs the driving assembly to drive
the pin assembly into the saw blade to stop the spinning of such
blade. In addition to or in the alternative of stopping the saw
blade, the sensing assembly causes power to the saw assembly to be
shut-off or for the blade to be mechanically moved away from the
user, and the like for preventing contact between the user and
working tool.
[0019] The video proximity device may utilize a number of different
techniques for detecting the presence of a human body part. In one
embodiment, the video from the video proximity device is analyzed
by an information handling system (e.g. a computer) having pattern
recognition hardware or software for identifying the unique shapes
and patterns of human body parts, as differentiated from the shapes
and patterns of a workpiece. For example, a human hand is comprised
of a series of rounded edges, while a workpiece generally includes
linear edges. In another embodiment, an information handling system
includes motion analysis hardware or software capable of detecting
the movement of a human body part, as differentiated from the
movement of a workpiece. For example, a human hand moves in a
non-linear, or somewhat erratic, manner, while a workpiece is
directed in a line parallel to the orientation of a tool element.
In a further embodiment, the video camera comprises a thermal
imaging camera, capable of distinguishing the heat signature of a
human body part from the heat signature of a workpiece. For
example, a human body part is typically of a higher temperature
than the temperature of a workpiece in the same environment, and
thus is distinguishable by such a system. It should be noted that
one of skill in the art may contemplate other video processing and
recognition techniques without departing from the scope and intent
of the present invention.
[0020] The video proximity device may be positioned in a number of
different orientations in order to provide a substantially
unobstructed view of the working tool element and the adjacent
area. In one embodiment, the video proximity device is mounted on
an assembly above the support surface. For example, in the case of
a table saw, a video camera is mounted on a support assembly above
the saw blade, providing a view of the blade and surrounding area.
In another embodiment, the video proximity device is mounted to the
power tool itself. For example, in the case of a table saw, a video
camera is mounted in the fence of the table saw, providing a
generally unobstructed view of the blade and surrounding area.
Additionally, fiber optic cameras may be desirable in order to
minimize intrusion and the like.
[0021] The video proximity device may be employed in concert with
various systems for alerting the operator of their encroachment
into a predefined zone or point. In one embodiment, the support
surface of the power tool is clearly marked to indicate the limits
of one or more predefined zones. For example, in the case of a
table saw, a "red zone" is clearly marked on the support surface,
indicating that if an operator's body part encroaches into this
zone, the saw blade will be stopped by driving a pin assembly into
the side of the saw blade. It should be noted that more than one
zone may be defined, and the video proximity device may be capable
of distinguishing encroachment into different zones. This may serve
not only to provide an additional signal to the operator, but also
to minimize the situations in which the pin assembly is actuated.
In the case of the table saw, the red zone is surrounded by a
caution zone or "yellow zone," for example. If an operator's hand
encroaches into the caution/yellow zone, power to the motor driving
the saw blade or the working tool is terminated, or the tool is
moved below a support surface, causing no permanent damage to the
saw blade. Such a configuration may have the added benefit of
providing a gradual slowdown for the working tool element. In the
case of a table saw utilizing a yellow zone/red zone combination,
for example, initially slowing the saw blade in the yellow zone
allows the blade to be stopped more quickly and more effectively in
the red zone, reducing potential harm to an operator and to the
power tool.
[0022] In another embodiment of the sensing assembly, a laser
device is used with the video proximity device for clearly marking
the boundaries of a zone. In one embodiment, the laser device
projects a beam of visible light onto the support
surface/workpiece, indicating to an operator the limits of the
zone. This configuration provides the added benefit of visually
indicating to the operator encroachment into the zone outlined by
the beam, which may appear on the encroaching part of the
operator's body.
[0023] Referring specifically to FIG. 1, a video proximity device
is shown for a table saw assembly 100 in accordance with an
exemplary embodiment of the first aspect of the present invention.
The table saw assembly 100 includes a saw blade 102 surrounded by a
red zone 104 and a caution zone/yellow zone 106. A video camera 110
is located directly above the table saw assembly 100, mounted on a
support assembly 112. The support assembly 112 provides passage for
cables 114 associated with the video camera 112. These cables
supply power to the video camera 110 and connect the output of the
video camera 110 to a computer or processor having hardware or
software for discerning the presence of a human body part in the
zones. Upon encroachment of a body part into the yellow zone 106,
action is taken by the table saw assembly 100 to stop the saw blade
102. This action may include eliminating power to a motor driving
the saw blade 102. Upon encroachment of a body part into the red
zone 104, action is taken by the table saw assembly 100 directed
toward stopping the saw blade 102 in a more definite manner. For
example, a pin assembly 126 is directed into the saw blade 102 or
the saw blade 102 is removed to below the support surface of the
table saw assembly 100.
[0024] Referring specifically to FIG. 2, a video proximity device
is shown for a table saw assembly 100 in accordance with an
exemplary embodiment of the present invention. The table saw
assembly 100 includes a saw blade 102 surrounded by a red zone 104
and a yellow zone 106. A video camera 110 is located directly above
the table saw assembly 100, mounted on a support assembly 112. The
support assembly 112 provides passage for cables 114 associated
with the video camera 112. These cables supply power to the video
camera 110 and connect the output of the video camera 110 to a
information handling system having hardware or software for
discerning the presence of a human body part in the red zone 104
and the yellow zone 106. A laser device 120 is included with the
video camera 110 and projects a laser beam 122 onto the
workpiece/support surface of the table saw assembly 100. Upon
encroachment of a body part into the yellow zone 106, an operator
is visually cued by the reflectance of the laser beam 122 from a
body part encroaching into the zone, and action may be taken by the
table saw assembly 100 to stop the saw blade 102. For example, such
action includes terminating power to a motor powering the saw blade
102. Further, upon encroachment of a body part into the red zone
104, action is taken by the table saw assembly 100 directed toward
stopping the saw blade 102 in a more definite manner. For example,
the pin assembly 126 is directed into the saw blade 102 or the saw
blade 102 is dropped below the support surface of the table saw
assembly 100.
[0025] Referring specifically to FIG. 3, a laser beam 122 is shown
contacting a body part 124 encroaching into a red zone 104 in
accordance with a first aspect of the present invention. The laser
beam 122 may serve as a visual cue to the operator that
encroachment into the red zone 104 has occurred. It should be noted
that the area enclosed by the laser beam 122 may correspond with
the red zone 104, the yellow zone 106 (See FIGS. 1 and 2), or any
number of predefined zones or points. It should also be noted that
an operator of a power tool utilizing a video proximity device may
define the area of a zone dynamically, and the laser beam 122 may
be used to indicate the boundaries of such a zone. It should her be
noted that a number of laser beam generating devices may be used to
indicate a number of different zones, as contemplated by one of
skill in the art.
[0026] In the alternative to the sensing assembly including a video
proximity device, such assembly may recognize the difference in the
electrical properties of wood and a user whereby the system
projects a high-frequency electrical signal on the saw blade and
monitors changes in the signal such as by utilizing one of the
assemblies presently known in the art. For example, under normal
operating conditions, the signal would remain unaltered for wood
includes a relatively small inherent electrical capacitance and
conductivity and therefore, the presence of wood in the electrical
field would not result in an alteration of such field. However, if
a user's hand made contact with the saw blade 102, the detection
system 100 would be activated by the sensing assembly detecting a
change in the electrical signal as a result of the relatively large
inherent capacitance of the user's body. For instance, contact
detection electrodes are coupled to the saw blade to detect
fluctuations in capacitance.
[0027] As illustrated in FIGS. 4-6, the stopping system disclosed
in the instant invention includes a pin assembly 126. The pin
assembly 126 is disposed on a first side of the saw blade 102 for
stopping a spinning saw blade. Further, the pin assembly 126
includes a first end. In one embodiment, the first end includes a
pointed tip for piercing the saw blade. In additional embodiments,
the pin assembly 126 is comprised of heat-treated steel thereby
increasing the strength and durability of the pin assembly 126. It
is contemplated that additional materials including steel or other
metals may be utilized without departing from the scope and spirit
of the present invention. Moreover, the size and shape of the pin
assembly 126 may vary depending upon the size and dimensions of the
saw blade 102 which is to be pierced; however, preferably, such
variation will be limited to that which will not result in the
significant disintegration of the saw blade 102.
[0028] In addition to the pin assembly 126, the stopping system
includes a driving assembly 128. In an exemplary embodiment, the
driving assembly 128 is coupled to the pin assembly 126 for driving
the pin assembly 126 into the spinning saw blade 102. Further, the
driving assembly 128 includes a communication system which allows
the driving assembly 128 to communicate with the sensing assembly.
For example, the driving assembly 128 may be hard-wired 130 to the
sensing assembly as demonstrated in FIG. 4. In additional
embodiments, the driving assembly 128 may be activated by the
sensing assembly via an optical signal from the sensing
assembly.
[0029] Moreover, in an exemplary embodiment of the present
invention, an explosive or capable of detonation substance is
coupled to a piston which upon actuation causes the pin assembly
126 to be propelled into the spinning saw blade. The explosive
actuated pin assembly 126 results in such assembly making an
instantaneous forced entry into the saw blade 102 causing the saw
blade 102 to stop spinning immediately. As such, in one embodiment,
the explosive substance is contained in a replaceable cartridge 132
(e.g. a blank cartridge including a .22 or a .27 caliber load). In
additional embodiments, the drive assembly 128 may be
electromagnetic, mechanical (e.g. a spring system or mallet
activated), or the like. It will be appreciated that activation of
the pin assembly 126 by the drive assembly 128 will generally
require the replacement of the explosive substance (e.g. the
replaceable cartridge, 132). However, use of a replaceable
cartridge system will allow a user to easily replace the explosive
substance prior to resuming use of the saw.
[0030] In a further embodiment of the present invention, a
receiving block 134 is disposed on the second side of the saw blade
102 for receiving the tip of the pin assembly 126. In one exemplary
embodiment, as illustrated in FIGS. 5 and 6, the receiving block
134 includes an aperture 136 for receiving the tip of the pin
assembly 126. Use of the aperture 136 allows the pin assembly 126
to be received by the receiving block 134 while minimizing the
damage to the pin assembly 126 due to interaction with the
receiving block 134. Further, the receiving block 134 may be formed
of any suitable metal including steel, heat-treated steel, or the
like so that contact by the pin assembly 126 does not destroy the
receiving block 134.
[0031] FIGS. 5 and 6 illustrate the pin assembly in either a
retracted position or an actuated position, respectively. In FIG.
5, the pin assembly 126 is in the retracted position and the
replaceable cartridge 132 is ready for use. In an exemplary
embodiment, upon sensing a user's hand or other body part in a
predefined zone, the sensing assembly (see FIGS. 1-3) directs the
driving assembly 128 to drive the pin assembly 126 into the rapidly
spinning saw blade 102. The driving assembly 128 actuates the pin
assembly 126 by firing the explosive substance contained in the
replaceable cartridge 132 causing the instantaneous firing of the
pin assembly 126 through the saw blade 102 into the receiving block
134. As illustrated in FIG. 6 and as discussed previously, the
receiving block 134 may be configured with an aperture 136 for
receiving the pin assembly 126. In an exemplary embodiment, the
size and shape of the aperture 136 corresponds to that of the pin
assembly 126.
[0032] In an additional embodiment, the pin assembly 126 may be
retracted from the saw blade 102 and the receiving block 134 by
blowing compressed air through a port hole 138 located within the
drive assembly 128. Such port hole 138 also functions as an exit
for the air generated during the release of the explosive
substance.
[0033] In still a further embodiment, the detection system 100 may
include a self-check feature whereby each time the table saw is
turned on, the detection system 100 performs a system check to
ensure that the system is properly working. If the system is not
properly working, the user may be notified by a warning signal
including flashing lights or power being cut to the motor. In an
additional embodiment, the detection system 100 may include a
bypass feature which would allow the system to be turned off if
necessary. For example, if the sensing assembly is triggered by
detecting a difference in capacity, if a user desires to cut a
piece of metal with such saw it would be preferable to turn-off the
detection system. The detection system may be set-off unnecessarily
whereby the capacitance of a piece of wood is much less than that
of a piece of metal and thus, the system may sense a change in
capacitance due to the type of material being cut not because of
entry of a users hand into a predefined zone. Those of skill in the
art will appreciate that while the present drawings illustrate the
present invention in use on a table saw, such invention may be
adapted to be coupled to variety of power tools including a miter
saw, chop saws, radial arm saws, circular saw, and the like without
departing from the scope and spirit of the present invention.
[0034] In addition to the detection system, a method for stopping a
spinning saw blade 200 is disclosed. As illustrated in FIG. 7, such
method is comprised of cutting material with a saw blade 202. Upon
detecting a user's hand in a pre-defined work zone by a detecting
system 204, the detecting system including a sensing device, a
drive assembly, a pin assembly and a receiving block transmits
directions from the sensing device to the drive assembly to drive
the pin assembly into the saw blade 206. The drive assembly then
drives the pin assembly 124 through the saw blade 104 into the
receiving block 130 to stop the saw blade 104 from spinning 208. It
is contemplated that the instant method 200 may be utilized with a
number of different power tools including a miter saw, circular
saw, chop saws, radial arm saws, table saw, and the like.
[0035] It is believed that the present invention and many of its
attendant advantages will be understood by the foregoing
description, and it will be apparent that various changes may be
made without departing from the scope and spirit of the invention
or without sacrificing all of its material advantages. The form
herein before described being merely an explanatory embodiment
thereof, it is the intention of the following claims to encompass
and include such changes.
[0036] Further, it is understood that the specific order or
hierarchy of steps in the methods disclosed are examples of
exemplary approaches. Based upon design preferences, it is
understood that the specific order or hierarchy of steps in the
method can be rearranged while remaining within the scope of the
present invention. The accompanying method claims present elements
of the various steps in a sample order, and are not meant to be
limited to the specific order or hierarchy presented.
* * * * *