A handheld portable cutting apparatus has a cutter unit with a cutter unit longitudinal axis. In a central housing section of the cutting apparatus, a drive connection is arranged between an electric drive motor and the cutter unit, wherein a motor housing having a motor housing longitudinal axis extends from the central housing section. A handle extends from the central housing section in a handle longitudinal axis. The cutter unit includes a guide bar with a saw chain circulating thereon, wherein, in a side view onto the cutting apparatus, the point of intersection between the handle longitudinal axis and the motor housing longitudinal axis and also the point of intersection between the handle longitudinal axis and the cutter unit longitudinal axis lie in the central housing section.

A handheld portable cutting apparatus has a cutter unit with a cutter unit longitudinal axis. In a central housing section of the cutting apparatus, a drive connection is arranged between an electric drive motor and the cutter unit, wherein a motor housing having a motor housing longitudinal axis extends from the central housing section. A handle extends from the central housing section in a handle longitudinal axis. The cutter unit includes a guide bar with a saw chain circulating thereon, wherein, in a side view onto the cutting apparatus, the point of intersection between the handle longitudinal axis and the motor housing longitudinal axis and also the point of intersection between the handle longitudinal axis and the cutter unit longitudinal axis lie in the central housing section.

The present disclosure relates to a tree harvesting machine (120) having a crane arm (118), wherein the crane arm (118) comprises a tree harvesting head (100; 200) arranged at a free end of the crane arm (118). The tree harvesting head (100) comprises a saw (104) and at least two feed wheels (102). The tree harvesting head (100) further comprises an electric motor (106a) arranged to drive the saw (104), and at least one electric motor (106b) arranged to drive the feed wheels (102). The present disclosure also relates to associated tree harvesting monitoring systems, tree harvesting heads, methods and computer programs.

The present disclosure relates to a tree harvesting machine (120) having a crane arm (118), wherein the crane arm (118) comprises a tree harvesting head (100; 200) arranged at a free end of the crane arm (118). The tree harvesting head (100) comprises a saw (104) and at least two feed wheels (102). The tree harvesting head (100) further comprises an electric motor (106a) arranged to drive the saw (104), and at least one electric motor (106b) arranged to drive the feed wheels (102). The present disclosure also relates to associated tree harvesting monitoring systems, tree harvesting heads, methods and computer programs.

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 handheld portable cutting apparatus has a cutter unit with a cutter unit longitudinal axis. In a central housing section of the cutting apparatus, a drive connection is arranged between an electric drive motor and the cutter unit, wherein a motor housing having a motor housing longitudinal axis extends from the central housing section. A handle extends from the central housing section in a handle longitudinal axis. The cutter unit includes a guide bar with a saw chain circulating thereon, wherein, in a side view onto the cutting apparatus, the point of intersection between the handle longitudinal axis and the motor housing longitudinal axis and also the point of intersection between the handle longitudinal axis and the cutter unit longitudinal axis lie in the central housing section.

A handheld portable cutting apparatus has a cutter unit with a cutter unit longitudinal axis. In a central housing section of the cutting apparatus, a drive connection is arranged between an electric drive motor and the cutter unit, wherein a motor housing having a motor housing longitudinal axis extends from the central housing section. A handle extends from the central housing section in a handle longitudinal axis. The cutter unit includes a guide bar with a saw chain circulating thereon, wherein, in a side view onto the cutting apparatus, the point of intersection between the handle longitudinal axis and the motor housing longitudinal axis and also the point of intersection between the handle longitudinal axis and the cutter unit longitudinal axis lie in the central housing section.

The disclosure relates to a chain saw having a housing and a drive motor. The guide bar is held on the housing by way of a releasable fastening arrangement and, when the fastening arrangement is released, by way of a tensioning device is displaceable in relation to the housing in the direction of the longitudinal axis of the guide bar. The chain saw includes a chain lifting device which is configured separately from the tensioning device. The chain lifting device in a deflected position of the chain lifting device is configured for deflecting the saw chain when the tensioning device tensions the saw chain, and in an operating position of the chain lifting device is configured for relaxing the saw chain when the guide bar is fixed.

The disclosure relates to a chain saw having a housing and a drive motor. The guide bar is held on the housing by way of a releasable fastening arrangement and, when the fastening arrangement is released, by way of a tensioning device is displaceable in relation to the housing in the direction of the longitudinal axis of the guide bar. The chain saw includes a chain lifting device which is configured separately from the tensioning device. The chain lifting device in a deflected position of the chain lifting device is configured for deflecting the saw chain when the tensioning device tensions the saw chain, and in an operating position of the chain lifting device is configured for relaxing the saw chain when the guide bar is fixed.

A chain saw may include a saw chain, a guide bar to which the saw chain is attached, a sprocket configured to run the saw chain along a periphery of the guide bar, a prime mover configured to rotate the sprocket, an oil tank configured to store oil to be supplied to the saw chain, a housing that houses the prime mover and the oil tank, a bolt protruding from the housing and penetrating a hole disposed in the guide bar, a nut screwed onto the bolt to fix the guide bar to the housing, and a heat dissipating structure configured to dissipate heat from the bolt to the oil in the oil tank.