A working machine may include a working unit having a longitudinal direction in a front-back direction, an electric motor configured to drive the working unit, a control unit configured to control the electric motor, a housing including a housing body and a grip, wherein the housing body holds the working unit and houses the electric motor and the control unit, and the grip extends from the housing body and is configured to be grasped by a user's hand, a battery pack attached to the housing and configured to supply electric power to the electric motor via the control unit, and a trigger lever disposed on the grip and configured to operate the electric motor by being pulled toward the grip by a finger of the user. A front end of the control unit may be disposed rearward of a rear end of the trigger lever.

A guide bar for a chain saw comprising two opposite elongate surfaces and a slot formed between said opposite sides running along the periphery of the guide bar, in order to receive and retain the chain during cutting. At least one of the elongate surfaces is furrowed across its surface in the direction of the cutting movement of the guide bar. The invention also relates to an apparatus for operating the chain saw in a forestry machine.

Multi-speed automatic transmissions for power tools are provided. A multi-speed automatic transmission includes an output shaft configured to be coupled to a chain sprocket to rotatably drive the chain sprocket, wherein the automatic transmission is configured to automatically shift between a plurality of gear ratios in response to a rotational speed of the output shaft reaching a preset rotational speed.

Multi-speed automatic transmissions for power tools are provided. A multi-speed automatic transmission includes an output shaft configured to be coupled to a chain sprocket to rotatably drive the chain sprocket, wherein the automatic transmission is configured to automatically shift between a plurality of gear ratios in response to a rotational speed of the output shaft reaching a preset rotational speed.

A chain saw may comprise a braking mechanism; a housing including a first space and a second space in which the braking mechanism is disposed; and an operation member. The housing may include a through hole communicating the second space to outside of the housing. The operation member may be disposed over the second space and the outside of the housing through the through hole. The operation member may be movable between a braking position where the operation member causes the braking mechanism to interrupt rotation of a saw chain and a driving position where the operation member causes the braking mechanism not to interrupt the rotation of the saw chain. The braking mechanism may comprise a connecting member that moves in the second space in conjunction with movement of the operation member. The housing may include an opening communicating the first space to the second space.

A chain saw may comprise a braking mechanism; a housing including a first space and a second space in which the braking mechanism is disposed; and an operation member. The housing may include a through hole communicating the second space to outside of the housing. The operation member may be disposed over the second space and the outside of the housing through the through hole. The operation member may be movable between a braking position where the operation member causes the braking mechanism to interrupt rotation of a saw chain and a driving position where the operation member causes the braking mechanism not to interrupt the rotation of the saw chain. The braking mechanism may comprise a connecting member that moves in the second space in conjunction with movement of the operation member. The housing may include an opening communicating the first space to the second space.

A chain saw disclosed herein may include a motor configured to rotate a saw chain about a guide bar, a control unit configured to control a voltage applied to the motor, a body housing that houses the motor and the control unit, a battery detachably attached to the body housing, and a top handle provided above the body housing. The control unit may be disposed above the battery. In a rear view of the chain saw in a state where the chain saw is placed on a mount surface, the battery and the control unit may not overlap. In a top view of the chain saw in the state where the chain saw is placed on the mount surface, the battery and the control unit may overlap at least partially.

A chain saw disclosed herein may include a motor configured to rotate a saw chain about a guide bar, a control unit configured to control a voltage applied to the motor, a body housing that houses the motor and the control unit, a battery detachably attached to the body housing, and a top handle provided above the body housing. The control unit may be disposed above the battery. In a rear view of the chain saw in a state where the chain saw is placed on a mount surface, the battery and the control unit may not overlap. In a top view of the chain saw in the state where the chain saw is placed on the mount surface, the battery and the control unit may overlap at least partially.

A cutting tool includes: a loop-wound chain wound about at least a drive crown activated in rotation by a motor, a lubricating circuit of the chain provided with a tank of lubricating fluid, a pump drawn by the motor and having an aspirating conduit of the fluid provided with an aspirating mouth located internally of the tank, and a delivery conduit provided with an outlet mouth located in proximity of the chain, a sensor able to detect the lubricating fluid in the lubricating circuit.

A cutting tool includes: a loop-wound chain wound about at least a drive crown activated in rotation by a motor, a lubricating circuit of the chain provided with a tank of lubricating fluid, a pump drawn by the motor and having an aspirating conduit of the fluid provided with an aspirating mouth located internally of the tank, and a delivery conduit provided with an outlet mouth located in proximity of the chain, a sensor able to detect the lubricating fluid in the lubricating circuit.