A power tool has a base defining a work surface, a rotary cutting blade extending through an opening in the work surface, a drive motor for imparting rotational movement to the cutting blade and a power train coupled between the drive motor and the cutting blade to transmit rotation movement from the drive motor to the cutting blade. A swing arm assembly carries the cutting blade and is pivotably supported on the base at a pivot axis. A latch support the swing arm assembly in an operating condition in which the cutting blade extends through the opening in the work surface and is configured to be released to permit the swing arm assembly to pivot about the pivot axis to a safety position in which the cutting blade is beneath the work surface. In one aspect of the present disclosure, the power tool includes a safety system operable in response to an emergency signal that includes a mechanism for stopping the rotation of the cutting blade, whereby the rotational inertia of the cutting blade is converted after the rotation is stopped to pivoting of the swing arm assembly carrying the blade when the rotation of the blade is stopped.

A power tool assembly includes a drop arm assembly including a drop arm frame and an arbor shaft configured to support a shaping device at least partially above a workpiece support surface, the drop arm assembly configured to move within a drop plane to drop the shaping device completely beneath the workpiece support surface, a belt operably connected to the arbor shaft and configured to rotate the arbor shaft through a slave pulley, the slave pulley having a slave pulley axis of rotation, a motor including a power shaft operably connected to the belt through a motor end pulley, the motor end pulley having a motor end pulley axis of rotation, and an orbit bracket configured to orbitally support the drop arm assembly, the orbit bracket defining a drop arm orbit axis located between the motor end pulley axis of rotation and the slave pulley axis of rotation.

Table saws are disclosed. The table saws can include a blade, an arbor, an arbor block, an elevation carriage, and a latch that connects the arbor block and the elevation carriage. The arbor block can have a first position in which the latch connects the arbor block and the elevation carriage, and a second position in which the latch does not connect the arbor block and the elevation carriage. The arbor block can pivot from the first position to the second position upon the occurrence of a retraction force. The table saw can include an actuator to cause the occurrence of the retraction force, and detection electronics to detect contact between the blade and a person. Woodworking machines with detection and reaction systems are also disclosed. A reaction system can include an explosive that causes retraction of a cutting tool.

A detection system for detecting a dangerous condition for an operator using a power tool of the type which has an exposed blade relative to a work surface and a protection system for minimizing, if not eliminating the possibility of a user being injured by contacting the blade. In one preferred embodiment of the present invention, a proximity detection system is capable of detecting the presence of a user near the blade of a table saw and a protection system that can either retract the blade below the work surface of the table saw or terminate the drive torque to the blade which can result in rapid stopping of the saw blade by a work piece that is being cut.

A power tool assembly includes a workpiece support surface, a throat opening defined in the workpiece support surface, an arbor shaft configured to support a shaping device, the arbor shaft positioned beneath the workpiece support surface and accessible through the throat opening, and a camming device rotatably mounted at a location adjacent to the throat opening, the camming device including a first camming surface portion configured to cam against a second camming surface potion of a throat plate inserted into the throat opening, thereby locking the throat plate within the throat opening.

Table saws are disclosed. The table saws can include a blade, an arbor, an arbor block, an elevation carriage, and a latch that connects the arbor block and the elevation carriage. The arbor block can have a first position in which the latch connects the arbor block and the elevation carriage, and a second position in which the latch does not connect the arbor block and the elevation carriage. The arbor block can pivot from the first position to the second position upon the occurrence of a retraction force. The table saw can include an actuator to cause the occurrence of the retraction force, and detection electronics to detect contact between the blade and a person. Woodworking machines with detection and reaction systems are also disclosed. A reaction system can include an explosive that causes retraction of a cutting tool.