A chainsaw which has a low profile chain cover and a chain bar tightening clutch system. The chain bar tightening clutch system can have a bar tightening knob which drives a clutch which governs the amount of pressure applied to the chain bar by operating the bar tightening knob. The chainsaw can have a chain bar tensioning system which can have a tensioning drive member in an offset position from the tensioning post which positions the tensioning post to achieve a chain tension and compact chainsaw design. The chainsaw can also have an oil cap with a lock channel having a detent with produces a sound when moved from a disengaged to an engage position with an oil reservoir.

A chainsaw which has a low profile chain cover and a chain bar tightening clutch system. The chain bar tightening clutch system can have a bar tightening knob which drives a clutch which governs the amount of pressure applied to the chain bar by operating the bar tightening knob. The chainsaw can have a chain bar tensioning system which can have a tensioning drive member in an offset position from the tensioning post which positions the tensioning post to achieve a chain tension and compact chainsaw design. The chainsaw can also have an oil cap with a lock channel having a detent with produces a sound when moved from a disengaged to an engage position with an oil reservoir.

A chain saw includes a chain, a guide plate, and a locking device for tensioning the chain. The locking device includes an operating member rotatable about a first axis, a driving member for driving the guide plate to move to tension the chain, a first clutch coupling with the operating member, and a second clutch including meshing teeth cooperating with the first clutch. The driving member is connected with the second clutch, each of the meshing teeth includes a first sloped surface having a first slop and a second sloped surface having a second slop, the absolute value of the first slope is greater than that of the second slope.

A chain saw includes a chain, a guide plate, and a locking device for tensioning the chain. The locking device includes an operating member rotatable about a first axis, a driving member for driving the guide plate to move to tension the chain, a first clutch coupling with the operating member, and a second clutch including meshing teeth cooperating with the first clutch. The driving member is connected with the second clutch, each of the meshing teeth includes a first sloped surface having a first slop and a second sloped surface having a second slop, the absolute value of the first slope is greater than that of the second slope.

Chainsaws and methods of operating chainsaws are provided. A chainsaw includes a guide bar supporting a chain; a motor configured to drive the chain, the motor receiving power from an electrical energy source of the chainsaw; a sprocket operably coupled between the motor and the chain to impart driving force from the motor to the chain; and an operating device operably coupled between the motor and the sprocket and moveable between a driving state and a neutral state, wherein the chain is freely moveable in at least one direction relative to the motor when the operating device is in the neutral state.

Chainsaws and methods of operating chainsaws are provided. A chainsaw includes a guide bar supporting a chain; a motor configured to drive the chain, the motor receiving power from an electrical energy source of the chainsaw; a sprocket operably coupled between the motor and the chain to impart driving force from the motor to the chain; and an operating device operably coupled between the motor and the sprocket and moveable between a driving state and a neutral state, wherein the chain is freely moveable in at least one direction relative to the motor when the operating device is in the neutral state.

A hand-held power tool comprising an internal combustion engine (4), a working tool (6), a centrifugal clutch (8), and a control system (10) is disclosed. The engine (4) has a clutch-in speed, above which the engine (4) drives the working tool (6). The control system (10) comprises a rotation speed sensor (12), and a speed limitation controller (14), which is configured to limit an engine speed at a limitation speed below the clutch-in speed. It is active or activated during a starting procedure of the internal combustion engine (4). The control system (10) is configured to deactivate the speed limitation controller (14) upon sensing at least one acceleration at a level above the limitation speed and sensing at least one deceleration at a level above the limitation speed, such that the engine (4) is rotatable above the limitation speed to drive the working tool (6).

A chainsaw which has a low profile chain cover and a chain bar tightening clutch system. The chain bar tightening clutch system can have a bar tightening knob which drives a clutch which governs the amount of pressure applied to the chain bar by operating the bar tightening knob. The chainsaw can have a chain bar tensioning system which can have a tensioning drive member in an offset position from the tensioning post which positions the tensioning post to achieve a chain tension and compact chainsaw design. The chainsaw can also have an oil cap with a lock channel having a detent with produces a sound when moved from a disengaged to an engage position with an oil reservoir.

A chainsaw which has a low profile chain cover and a chain bar tightening clutch system. The chain bar tightening clutch system can have a bar tightening knob which drives a clutch which governs the amount of pressure applied to the chain bar by operating the bar tightening knob. The chainsaw can have a chain bar tensioning system which can have a tensioning drive member in an offset position from the tensioning post which positions the tensioning post to achieve a chain tension and compact chainsaw design. The chainsaw can also have an oil cap with a lock channel having a detent with produces a sound when moved from a disengaged to an engage position with an oil reservoir.

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.