A power tool includes a function member, a motor, a driving circuit electrically connected to the motor to drive the motor, and a first control module configured to output a first control signal to the driving circuit. The first control module has a first working state and a first failure state. The first control module outputs a first working signal when the first control module is in the first working state, and outputs a first failure signal when the first control module is in the first failure state. A second control module is electrically connected to the first control module to receive the first working signal or the first failure signal from the first control module. The second control module outputs a second control signal to turn off the motor when the second control module receives the first failure signal from the first control module.

A power tool operator protection system comprises a plurality of wearable position sensors configured to be worn by an operator of a handheld power tool; a power tool position sensor configured to detect the position of a handheld power tool; and processing equipment configured to generate a model of the operator based on the mutual positions of the respective wearable sensors relative to each other, the mutual positions defining the operator's posture; associate each of a plurality of limbs (32a-g) of the operator with a respective protection volume (30a-g); and based on the position and/or motion of the power tool in relation to the protection volume (30a-g) indicating an imminent danger that the working implement enters a protection volume (30a-g), generate a protection signal.

A chain saw includes a housing, the housing including a first housing, a second housing, and a receiving cavity formed by the first housing and the second housing; a cutter including a blade chain and a blade bar for supporting the blade chain, the cutter being mounted on the housing; a power assembly, the power assembly including a drive unit for driving the cutter and a power supply unit for supplying power to the drive unit; a front handle connected to the second housing and surrounding the first housing, the front handle including a grip portion, a first and second fixing parts which are located at two ends of the grip portion, the first fixing part abutting on the side wall of the second housing, and the second fixing part being located at the bottom of the housing and connecting with the second housing.

The present invention generally relates to improvements in chainsaws. In particular, the present invention relates to mechanisms for preventing the chain of a chainsaw from falling off the guide bar of the chain saw. According to one embodiment, a magnetic chainsaw chain retention mechanism comprising a magnetic guide bar is provided. The mechanism maintains the chain of a chainsaw on the chainsaw guide bar during use of the chainsaw. As heat expands the overall length of the chain while the chainsaw is running, a magnetic force attracts the chain to the guide bar thus preventing it from falling off. In another embodiment, a magnetic chain is provided, such that the chain remains attracted to the guide bar, wherein, a magnetic force attracts the chain to the guide bar if and when it expands thus preventing it from falling off the guide bar.

A power tool includes a switch moveable between a first position enabling activation of a motor and a second position disabling the motor. The power tool includes a trigger movably coupled to a housing of the power tool between an OFF position and an ON position. The switch moves from the second position to the first position in response to the trigger moving from the OFF position to the ON position. The power tool includes a trigger lock-off pivotably coupled to the housing between a lock position and an unlock position. The trigger lock-off is engageable with the trigger to inhibit movement of the trigger from the OFF position to the ON position when the trigger lock-off is in the lock position. The trigger lock-off allows movement of the trigger from the OFF position to the ON position when the trigger lock-off is in the unlock position.

A hanger for suspending a chainsaw in a display is provided. The display may include a bar assembly, and the bar assembly may include two parallel bars that are configured to project substantially parallel to each other and a ground plane. The hanger may include a body, and the body may have a first end, a second end, and an elongated plate-like member defining a first face and a second face. The hanger may also include a first interface portion disposed at the first end of the body, and the first interface portion may include a first aperture and a second aperture. The hanger may additionally include a second interface portion disposed at a portion of the body proximate to the second end, and a portion of the first face of the body may extend along a guide bar of the chainsaw. The second interface portion may align with a receiving orifice formed in the guide bar to enable a releasable fastener to operably couple the guide bar to the hanger. The first and second apertures of the first interface portion may be configured to slidingly engage with the bars of the bar assembly to suspend the chainsaw from the bar assembly such that a longitudinal length of the guide bar extends substantially perpendicular to the ground plane.

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 cutting device includes a housing formed with a handle portion and an accommodation portion, a cutting portion connected to the housing and at least partially disposed in the accommodation portion, a motor disposed in the accommodation portion and extending in a first linear direction, and a bottom plate extending in a plane of the bottom plate and formed with an opening through which at least part of the cutting portion passes. The cutting device further includes a worm gear and worm structure disposed in the accommodation portion. The cutting portion includes a chain and a guide plate connected to the housing and used for supporting the chain. The motor includes an output shaft, the cutting portion is connected to a driving shaft, the output shaft transmits power to the driving shaft through a worm gear and a worm, and the driving shaft is capable of driving the chain.

The present invention provides a chain saw includes a housing, the housing including a first housing, a second housing, and a receiving cavity formed by the first housing and the second housing; a cutter including a blade chain and a blade bar for supporting the blade chain, the cutter being mounted on the housing; a power assembly, the power assembly comprising a drive unit for driving the cutter and a power supply unit for supplying power to the drive unit; a front handle connected to the second housing and surrounding the first housing, the front handle comprising a grip portion, a first and second fixing parts which are located at two ends of the grip portion, the first fixing part abutting on the side wall of the second housing, and the second fixing part being located at the bottom of the housing and connecting with the second housing.

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.