A power tool assembly includes a drop arm assembly rotatably supporting an arbor shaft and movable between a first drop arm position and a second drop arm position, an actuating device configured to transfer a force to the drop arm assembly when the drop arm assembly is at the first drop arm assembly position, a control system configured to control the actuating device to transfer the force to the drop arm assembly when an unsafe condition is sensed, a motor operably connected to the arbor shaft through a gear, and a gear housing which houses the gear, the gear housing formed from a non-conductive material.

A workpiece limiting device for power tools includes a support arm adapted to contact with a workpiece and limit the workpiece, and a body. The support arm is supported by the body and movable relative to the latter. The workpiece limiting device further includes a quick-release device. The quick-release device allows manual adjustment of the position of the support arm relative to the body and locks this position without using an external tool. Through the workpiece limiting device, the adjustment range of the position of the support arm relative to the power tool can be greatly expanded, and workpieces in different sizes can be processed.

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 method of resetting a drop arm assembly in a power tool assembly from a first drop arm assembly position whereat a portion of a shaping device mounted on the drop arm assembly does not extend above a workpiece support surface, includes removing a throat plate from a throat plate opening, moving at least a portion of a blade wrench downwardly through the throat plate opening, operably coupling the blade wrench with an arbor shaft of a drop arm assembly, releasing a first latch from engagement with a drop arm frame of the drop arm assembly after removing the throat plate, pulling the coupled blade wrench in an upwardly direction to a second drop arm assembly position whereat the portion of the shaping device extends above a workpiece support surface, and latching the drop arm assembly at the second drop arm assembly position with a second latch.

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. 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.

An object detection system in a saw includes an electrically conductive plate positioned at a predetermined distance from the implement, a detection circuit comprising a transformer, and a single cable connecting first terminal and second terminals of the transformer. The single cable includes a first conductor electrically connected to the first terminal of the winding and to the electrically conductive plate, a second conductor electrically connected to the implement, and an electrical insulator positioned between the first conductor and the second conductor.

A power tool assembly includes a drop arm assembly movable along a drop plane, an actuating device configured to transfer a force to the drop arm assembly to force the drop arm assembly along the drop plane, and a tool control unit assembly configured to control the power tool assembly, the tool control unit assembly including a printed circuit board (PCB) generally defining a PCB plane which is not perpendicular to the drop plane.

An object detection system in a saw includes an electrically conductive plate positioned at a predetermined distance from the implement, a detection circuit comprising a transformer, and a single cable connecting first terminal and second terminals of the transformer. The single cable includes a first conductor electrically connected to the first terminal of the winding and to the electrically conductive plate, a second conductor electrically connected to the implement, and an electrical insulator positioned between the first conductor and the second conductor.

A power tool assembly includes a drop arm frame with an opening configured to rotatably support an arbor shaft, a lower surface spaced apart from the opening, and a plurality of ribs extending between the lower surface and the opening. The plurality of ribs define a respective one of a plurality of axes, the plurality of axes intersect at a locus, and the locus is adjacent to, but spaced apart from, a center of gravity of the drop arm assembly. The power tool assembly further includes an actuating device configured to transfer a force to the drop arm assembly when the drop arm assembly is at the first drop arm assembly position, and a control system configured to control the actuating device to transfer the force to the drop arm assembly when an unsafe condition is sensed.

A method for measuring brush wear in a motor of a saw includes generating, with a sensor connected to a brush in a motor of the saw, a first signal corresponding to a level of wear in the brush and identifying, with a controller, a level of wear for the brush with reference to the first signal. The method further includes generating, with the controller and a user interface device, an output requesting replacement of the brush in response to the identified level of wear exceeding a predetermined threshold.