Power saws and features for power saws are disclosed. Various features are particularly relevant to jobsite or benchtop table saws, such as a trunnion formed from a shaped tube, an elevation carriage, and an arbor block retention mechanism. Other features are particularly relevant to table saws, hand-held circular saws, track saws, miter saws, and band saws with active injury mitigation technology, such as an electrically isolating gear and an overmolded arbor/gear element.

Power saws and features for power saws are disclosed. Various features are particularly relevant to jobsite or benchtop table saws, such as a trunnion formed from a shaped tube, an elevation carriage, and an arbor block retention mechanism. Other features are particularly relevant to table saws, hand-held circular saws, track saws, miter saws, and band saws with active injury mitigation technology, such as an electrically isolating gear and an overmolded arbor/gear element.

Power tools with conductive couplings used with active injury mitigation technology are disclosed. Conductive couplings are particularly relevant to table saws, hand-held circular saws, track saws, miter saws, and band saws with active injury mitigation technology. Conductive couplings provide a mechanism through which an electrical signal can be coupled or imparted to a blade, and then monitored for changes indicative of human contact with the blade. An exemplary conductive coupling includes a brush that establishes an electrical connection with a moving part of a power tool, and the brush maintains contact with the moving part of the power tool during at least 40 hours of cumulative time when the motor is spinning the arbor and blade without an interruption in the electrical connection sufficient to trigger the reaction system. A conductive coupling may be two-sided compliant. A conductive coupling may connect to a motor shaft to minimize electrical noise.

A protective apparatus and a machine tool are provided. The machine tool includes an operational element, a driving element, and the protective apparatus. The operational element and the driving element are disposed on machine table. The protective apparatus includes an insulating unit, conducting unit, capacitance sensor, and control unit. The insulating unit is disposed between the operational element and the driving element. The driving element drives the operational element by the insulating unit. The conducting unit contacts the operational element. The capacitance sensor electrically connects the conducting unit for sensing capacitance of the conducting unit. The control unit electrically connects the capacitance sensor and the driving element and determines whether a user approaches the operational element based on the capacitance. When the control unit detects that the distance between the user and the operational element is too close, the control unit stops the operation of the operational element.

A saw apparatus includes a guide bar, a chain driver, and an endless cutting chain trained about the guide bar and the chain driver. The guide bar includes a first chain retention feature along at least a portion of its periphery, and the cutting chain includes a second chain retention feature configured to interact with the first chain retention feature such that movement of the second chain retention feature away from the guide bar is restricted. A timber-working device includes a frame, at least one pair of arms pivotally attached to the frame and configured to be controlled to grasp at least one tree, and the saw apparatus mounted to the frame.

A cutter machine may include a cutter unit, a prime mover configured to drive the cutter unit, a housing including a housing body and a grip, wherein the housing body holds the cutter unit and houses the prime mover, and the grip extends from the housing body and is configured to be grasped by a user's hand, and a hand guard attached to the housing, configured to protect fingers of the user's hand grasping the grip, and being more deformable than the housing.

Power saws and features for power saws are disclosed. Various features are particularly relevant to jobsite or benchtop table saws, such as a trunnion formed from a shaped tube, an elevation carriage, and an arbor block retention mechanism. Other features are particularly relevant to table saws, hand-held circular saws, track saws, miter saws, and band saws with active injury mitigation technology, such as an electrically isolating gear and an overmolded arbor/gear element.

Power saws and features for power saws are disclosed. Various features are particularly relevant to jobsite or benchtop table saws, such as a trunnion formed from a shaped tube, an elevation carriage, and an arbor block retention mechanism. Other features are particularly relevant to table saws, hand-held circular saws, track saws, miter saws, and band saws with active injury mitigation technology, such as an electrically isolating gear and an overmolded arbor/gear element.

A power tool includes a motor; an arbor attachment mechanism that includes a shaft configured to be driven by the motor about a spin axis. The arbor attachment mechanism is configured to hold a blade onto the shaft. The power tool includes a blade size limiter that is configured to prevent attachment of a blade with a radius greater than a predetermined size, and is configured to be connected to the arbor attachment mechanism independently of the attachment of the blade to the arbor attachment mechanism and such that the blade size limiter is at a distance from the spin axis of the shaft.

A power tool includes a motor; an arbor attachment mechanism that includes a shaft configured to be driven by the motor about a spin axis. The arbor attachment mechanism is configured to hold a blade onto the shaft. The power tool includes a blade size limiter that is configured to prevent attachment of a blade with a radius greater than a predetermined size, and is configured to be connected to the arbor attachment mechanism independently of the attachment of the blade to the arbor attachment mechanism and such that the blade size limiter is at a distance from the spin axis of the shaft.