A power tool assembly includes a drop arm assembly movable along a drop path between a first drop arm assembly position whereat a portion of a shaping device supported by the drop arm assembly extends above a workpiece support surface and a second drop arm assembly position whereat the portion of the shaping device does not extend above the workpiece support surface, an actuator housing configured to house a first actuating device at an active location at which a force from the first actuating device is transferred to the drop arm assembly, the actuator housing including a slit configured to position a second actuating device at an inactive location, and a control system configured such that when the first actuating device is housed, the control system controls the first actuating device to transfer the force to the drop arm assembly when an unsafe condition is sensed.

Various safety systems for power tools, and in particular table saws include detection systems for detecting a dangerous condition relative to a blade of the power tool, reaction systems for taking mitigation action in response to detection of a dangerous condition. The safety system may detect, prevent, and/or mitigate a dangerous condition associated with the power tool.

Table saws and table saws designed to implement safety systems that detect contact between a person and a dangerous portion of the saw are disclosed. Table saw components, mounting systems for table saws, and table saw attachments are also disclosed. One embodiment may include a first clamp surface, a second clamp surface spaced apart from the first clamp surface so that a base portion of a riving knife or splitter can be placed between the clamp surfaces with the opposing sides of the base portion generally parallel to the first and second clamp surfaces.

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 an arbor shaft configured to support a shaping device, a belt operably connected to the arbor shaft and configured to rotate the arbor shaft, a motor including a power shaft operably connected to the belt through a motor end pulley, and a positioning device operably connected to the motor, the positioning device configured to rotate the motor about a motor mounting axis of rotation which is offset from an axis of rotation of the motor end pulley, thereby modifying a tension of the belt.

In one embodiment, a table saw assembly includes a motor assembly, an electrically conductive belt operably connected to the motor assembly, an arbor shaft operably connected to the belt, a drop arm assembly rotatably supporting the arbor shaft, a first pulley rotatably supporting the belt, the first pulley including an inner component defining an inner bore and an outer component defining an outer surface, the first pulley configured to electrically isolate the inner bore from the outer surface, and an alignment adjustment mechanism operably connected to the first pulley, the alignment adjustment mechanism configured to selectably position the first pulley along an axis of rotation of the first pulley.

A method for detection of a fault in a sensing cable within a saw detects potential failures in a sensing cable that is part of an object detection system in the saw. The method includes generating a predetermined excitation signal transmitted through a first conductor and a second conductor in the sensing cable, detecting a return signal from the first conductor and the second conductor in the sensing cable in response to the predetermined excitation signal, identifying a signal-to-noise ratio (SNR) of the return signal, and generating an output indicating a fault in the sensing cable in response to the SNR of the return signal being below a predetermined value.

Various safety systems for power tools, and in particular table saws include detection systems for detecting a dangerous condition relative to a blade of the power tool, reaction systems for taking mitigation action in response to detection of a dangerous condition. The safety system may detect, prevent, and/or mitigate a dangerous condition associated with the power tool.

Table saws and table saws designed to incorporate safety systems are disclosed. The table saws may include vertical slide elevation mechanisms positioned toward the rear of the saw and constructed so that an arbor block and blade can retract when a safety system detects an unsafe condition. Other table saw parts and components are also disclosed.

A method of mounting a capacitive coupling plate to a power tool assembly including a drop arm assembly, an actuating device configured to transfer a force to the drop arm assembly, and a control system configured to control the actuating device includes connecting a capacitive coupling plate bracket formed from a non-conductive material to a drop arm frame of the drop arm assembly, and mounting the capacitive coupling plate to the capacitive coupling plate bracket.