A electric power tool, comprising a control system electrically coupled to a power supply and a motor to supply current to the motor, where the motor may be coupled to a driven element of a tool so as to drive the driven element. The control system may have a continuous power mode and a boost power mode to supply current to the motor at a greater amount than in continuous power mode, and may be configured to switch between the continuous power mode and the boost power mode based upon a sensed load on the electric motor. In some embodiments, the control system may switch to a cutback power mode to supply current to the motor at a lower amount than in continuous power mode is the load does not decrease before a predetermined time elapses.

A electric power tool, comprising a control system electrically coupled to a power supply and a motor to supply current to the motor, where the motor may be coupled to a driven element of a tool so as to drive the driven element. The control system may have a continuous power mode and a boost power mode to supply current to the motor at a greater amount than in continuous power mode, and may be configured to switch between the continuous power mode and the boost power mode based upon a sensed load on the electric motor. In some embodiments, the control system may switch to a cutback power mode to supply current to the motor at a lower amount than in continuous power mode is the load does not decrease before a predetermined time elapses.

Herein a hand-held power tool comprising an internal combustion engine (4) is disclosed. The hand-held power tool comprises, a working tool (6), a centrifugal clutch (8), and a control system (10). The internal combustion engine (4) has a clutch-in speed (C) above which the internal combustion engine (4) drives the working tool (6). A speed limitation controller (14), is configured to limit an engine speed at a limitation speed below the clutch-in speed (C). The control system (10) is configured to calculate an integral of the rotational speed of the internal combustion engine (4), and to deactivate the speed limitation controller (14) after the integral reaches an integration limit value, such that the internal combustion engine (4) is rotatable above the limitation speed (L) to drive the working tool (6) via the centrifugal clutch (8).

Herein a hand-held power tool comprising an internal combustion engine (4) is disclosed. The hand-held power tool comprises, a working tool (6), a centrifugal clutch (8), and a control system (10). The internal combustion engine (4) has a clutch-in speed (C) above which the internal combustion engine (4) drives the working tool (6). A speed limitation controller (14), is configured to limit an engine speed at a limitation speed below the clutch-in speed (C). The control system (10) is configured to calculate an integral of the rotational speed of the internal combustion engine (4), and to deactivate the speed limitation controller (14) after the integral reaches an integration limit value, such that the internal combustion engine (4) is rotatable above the limitation speed (L) to drive the working tool (6) via the centrifugal clutch (8).

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 battery-powered portable cutting tool includes a housing, a cutting element, an electric motor to drive the cutting element to cut, a battery to supply electric current to the motor and a control circuit to control the supply of electric current to the motor from the battery. The control circuit may include a main switch and an auxiliary switch. The control circuit may have an active state in which the main switch allows electric current to flow to the motor and an inactive state in which the main switch does not allow electric current to flow to the motor. The operation of the auxiliary switch causes the control circuit to change between the active and inactive states. The auxiliary switch is arranged to determine whether the tool is in an inappropriate state to be used and, if so, cause the control circuit to change to the inactive state.

To provide an easy-to-use electric chainsaw that uses, in place of a large battery pack with a high voltage rating that would have been used in conventional electric chainsaws, a battery power source composed of a set of small commonly used battery packs of the same rating. An electric chainsaw having a built-in electric motor that is powered by a rechargeable battery, wherein a set of commonly used battery packs of the same rating is used as the rechargeable battery. The set of battery packs is mounted at the back of the main housing so that the center of gravity (G) of the chainsaw is positioned within a range (R) of 1.5 time the width (W) of the grip section of a rear handle between the left and right sides of a center line that is centered in the horizontal direction.

To provide an easy-to-use electric chainsaw that uses, in place of a large battery pack with a high voltage rating that would have been used in conventional electric chainsaws, a battery power source composed of a set of small commonly used battery packs of the same rating. An electric chainsaw having a built-in electric motor that is powered by a rechargeable battery, wherein a set of commonly used battery packs of the same rating is used as the rechargeable battery. The set of battery packs is mounted at the back of the main housing so that the center of gravity (G) of the chainsaw is positioned within a range (R) of 1.5 time the width (W) of the grip section of a rear handle between the left and right sides of a center line that is centered in the horizontal direction.

To satisfy both a request for ensuring worker's safety at the engine start and a worker's request for promptly starting a work, on the premise of a working machine including an engine RPM suppression mode. A working machine (1) has a centrifugal clutch (6). The engine RPM suppression mode is executed at the start of an internal combustion engine (2). With the RPM suppression mode, the RPM of the internal combustion engine (2) is controlled not to exceed a clutch-in RPM. The working machine (1) has a mode cancelling means (S5) canceling the engine RPM suppression mode when a predetermined mode cancelation condition for cancelling the engine RPM suppression mode is satisfied, and a cancellation condition changing means (S2) changing the mode cancelation condition depending on a change in an engine operational state and/or an environment.