According to examples, a power tool may include a chassis and a guide bar mounted to the chassis, the guide bar having a central axis. The power tool may also include a handle attached to the chassis above the central axis of the guide bar and a motor housed within the chassis to drive a chain around the guide bar, in which the motor is positioned beneath the central axis of the guide bar and a central axis of the motor is at a certain angle with respect to the central axis. The handle, the motor, and the battery pack mount may be positioned with respect to the chassis to cause the power tool to substantially be balanced in both lateral and longitudinal directions about a location near the trigger mechanism when the battery pack is mounted to the battery pack mount.

A chainsaw includes a handle with a handgrip; an electric motor for endlessly moving a saw chain; a control unit for controlling rotation of the motor; and a main power switch switchable between an ON state and an OFF state. The handgrip is provided with a gripping detection device for detecting whether the handgrip is gripped by the worker, and the chainsaw is configured to, when the control unit is manipulated to deactivate the electric motor in a state in which the gripping detection device detects that the handgrip is gripped, maintain the main power switch in the ON state, and to, when the control unit is manipulated to deactivate the electric motor in a state in which the gripping detection device detects that the handgrip is not gripped, switch the main power switch to the OFF state.

A machine tool device includes at least one motor-driven machining tool; at least one sensor unit, in particular a capacitive sensor unit, which is configured to detect at least one foreign body in at least one detection area around the machining tool; and at least one open-loop and/or closed-loop control unit configured to trigger at least one action in accordance with at least one signal from the sensor unit. The sensor unit includes at least one antenna configured to emit at least one electric and/or magnetic field defining the at least one detection area and/or to detect the at least one foreign body in accordance with at least one change in at least one electric and/or magnetic field.

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 method is provided for detecting a substance, preferably human tissue, in the vicinity of a mobile tool, wherein the substance to be detected has different electrical characteristics from a material that can be processed by the mobile tool. In the method, a change is detected in a capacitance formed by the tool and a counter electrode that is electrically insulated from the tool. A periodic change in the capacitance is detected and the change is produced by the presence of the substance in a region in relation to the tool and by a periodic change in a geometrical characteristic of the tool in this region as the tool moves.

A method is provided for detecting a substance, preferably human tissue, in the vicinity of a mobile tool, wherein the substance to be detected has different electrical characteristics from a material that can be processed by the mobile tool. In the method, a change is detected in a capacitance formed by the tool and a counter electrode that is electrically insulated from the tool. A periodic change in the capacitance is detected and the change is produced by the presence of the substance in a region in relation to the tool and by a periodic change in a geometrical characteristic of the tool in this region as the tool moves.

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.

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.

Method, apparatus, and system for operation of a timber-working device configured to perform at least one operation having an associated hazard zone. At least one signal from at least one orientation sensor associated with the timber-working head may indicate whether a predetermined location is within the hazard zone based on the orientation of the timber-working head. Operation of the timber-working head can be controlled based on the signal.

Method, apparatus, and system for operation of a timber-working device configured to perform at least one operation having an associated hazard zone. At least one signal from at least one orientation sensor associated with the timber-working head may indicate whether a predetermined location is within the hazard zone based on the orientation of the timber-working head. Operation of the timber-working head can be controlled based on the signal.