On 03/11/2010 06:49 PM, Chris Friesen wrote:
On 03/11/2010 06:12 PM, zzzzzzzzzz wrote:
Have you read the patent claims?
"1. A table saw comprising: a frame structure with a generally flat work
surface; a rotatable circular blade mounted on an arbor and being adapted
to have at least a portion of said blade extending above the flat work
surface in position to cut a work piece; a drive motor with an output shaft
mounted to the frame structure for powering the saw blade; a sensing
mechanism for generating at least a first actuation signal responsive to
predetermined sensed characteristics relating to the existence and/or
movement of a person in close proximity thereto; a retracting mechanism
located beneath said work surface for rapidly moving the blade downwardly
below the work surface responsive to said first actuation signal being
received.
Just to clarify, the patent you're quoting from isn't actually a Sawstop
patent.
The main sawstop patents are 20020069734 and 20020170399.
Sorry, my bad. Those are applications. Gass' patents are below. The
main sawstop patents are the first three.
US7617752 - Contact detection system for power equipment - 11/17/2009
A woodworking machine having one or more dangerous portions is
disclosed. The machine also includes a safety system configured to
detect accidental contact between a person and at least one of the
dangerous portions by electrically coupling a signal to the person's
body, and detecting if the signal becomes coupled to the dangerous portion.
US7600455 - Logic control for fast-acting safety system - 10/13/2009
Woodworking machines including cutting tools and motors adapted to drive
the cutting tools are disclosed. The machines also include a detection
system adapted to detect a dangerous condition between the cutting tool
and a person, and a reaction system adapted to perform a specified
action upon detection of the dangerous condition. The machines further
include a control system adapted to test the operability of at least a
portion of the detection system and/or the reaction system. The control
system is adapted to disable the motor if the tested portion is inoperable.
US20090236012 - Detection systems for power equipment - 09/24/2009
Methods to detect when a human body contacts a predetermined portion of
a machine are disclosed. The methods distinguish contact with a person
from contact with other materials. The methods are particularly
applicable in woodworking equipment such as table saws to distinguish
contact between a person and the blade of the saw from contact between
the blade and wet or green wood. The methods and woodworking equipment
may include predictive blade stop algorithms that prevent unnecessary
activations of a safety brake during coast down of a blade and continued
protection in the event a main power switch is turned off.
US20090293692 - Table saw throat plates and table saws including the
same - 12/03/2009
Throat plates for table saws and table saws including the same are
disclosed. In some embodiments, the throat plates and/or saws include at
least one securement mechanism adapted to secure and prevent inadvertent
removal of the throat plate from the throat of the saw. In some
embodiments, at least one of the securement mechanisms also provides a
height adjustment mechanism and/or prevents vertical removal of the
throat plate. In some embodiments, the throat plate includes an
accessory mounting port that provides a portal for accessories,
including safety accessories, to extend through the plate from beneath
the table of the saw. In some embodiments, the port extends from the
plate's outer perimeter to divide the plate's rear end portion into a
pair of spaced-apart members. In some embodiments, these members are
independently secured to the table saw and retained apart from each
other by one or more of the securement mechanisms.
US7621205 - Band saw with safety system - 11/24/2009
A band saw including a frame, at least two, spaced apart, rotatable
wheels supported by the frame, a blade looped around the wheels, where
rotation of at least one wheel causes the blade to move around the
wheels, a detection system adapted to detect a dangerous condition
between a person and the blade, and a reaction system configured to
engage and stop the blade within 10 milliseconds after detection of the
dangerous condition is disclosed. The reaction system may be configured
to cut and grip the blade.
Chris