An electric tool includes a drive structure, a motor, a driver circuit, and a controller. The controller is configured to output a first control signal to control the motor to drive the drive structure to operate in a first operation mode for a preset period of time in response to receiving a start instruction. After the preset period of time, the controller will output a second control signal to control the motor to drive the drive structure to operate in a second operation mode to a preset state. The first operation mode and the second operation mode are two opposite operation modes.

A system for protecting an operator (110) of a power tool may include a first set of wearable sensors (120) worn by the operator (110), a second set of wearable sensors (130) worn by the operator (110), a first tool sensor (122) disposed at the power tool where the first tool sensor (122) is configured to communicate with the first set of wearable sensors (120), a second tool sensor disposed (132) at the power tool where the second tool sensor (132) is configured to communicate with the second set of wearable sensors (130), and a controller (140). The controller (140) may be configured to determine, based on distances between the first tool sensor (122) and the first set of wearable sensors (120) and between the second tool sensor (132) and the second set of wearable sensors (130), whether to initiate a protective action with respect to the power tool.

A gardening and/or forestry apparatus has a support element. The support element supports an eyelet. The eyelet is configured to incorporate an apparatus securing element. The gardening and/or forestry apparatus also has an element receiving device. The support element and the element receiving device are configured to receive the support element in the element receiving device either in a first rotational position or in a second rotational position differing from the first rotational position and to secure the support element against rotation by form-fitting to the element receiving device.

A chainsaw may include a saw chain; a guide bar, a sprocket, a prime mover, a housing, a sprocket cover, and a guide member. The guide bar, the housing and the sprocket cover may define a chain passage. The guide member may include a first facing surface having an arc shape centered on the rotation axis and a second facing surface having an arc shape centered on a position offset from the rotation axis. When the chainsaw is placed on a horizontal mounting surface and viewed in the direction along the rotation axis, an angle between (i) a straight line connecting the rotation axis and a position where the first facing surface and the second facing surface are connected and (ii) a horizontal plane may be in a range of −10 degrees to 25 degrees.

The invention relates to a method for operating a work apparatus having a combustion engine. An ignition device is provided for triggering an ignition spark at a spark plug for igniting a fuel/air mixture in a combustion chamber of the combustion engine. The combustion chamber is bounded by a piston which drives a crankshaft in a rotating manner. In order to avoid the combustion engine stopping in rich mode, the speed (n) of the combustion engine is monitored over the period of time (t, ΔT) and the ignition point (ZZP) of the ignition device is advanced if the speed (n) of the combustion engine lies within a predefined speed range (n.sub.min; n.sub.max) within a predefined period of time (t, ΔT) and then the speed n drops below a speed limit value (n.sub.G).

Improved chain saws, components for chain saws, methods of making chain saws and components, and methods of using chain saws and components are disclosed. In some embodiments, a chain saw comprises a saw bar and a plurality of links, wherein a first link has a hook that engages a recess of a second link, thereby coupling the first link and the second link and allowing them to articulate without decoupling. The saw bar may have a rail, and the links may have grooves such that the links straddle and ride over the rail. The rail may have a projection and the grooves of the links may have notches accommodating the projection such that the projection prevents dislocation of the links. The links may have conical or pyramidal cutting teeth. The chain may be bidirectional. Robotic and automated operation of saws and other instruments are also disclosed.

An engine is configured such that, during the starting of the engine, when it is being detected that throttle opening has been set at a starting position, if it is detected that the engine speed has exceeded a predetermined speed slightly lower than a speed when a centrifugal clutch becomes an engaged state, a control unit retards the ignition timing from a general angle to a first angle BTDC, and then advances the ignition timing to a second angle at predetermined intervals, and holds the ignition timing at the second angle for a predetermined time period, thereby preventing the engine from stopping due to fouling on the spark plug while suppressing the engine speed at the speed when the centrifugal clutch becomes the engaged state, or less.

An electric tool includes a drive structure, a motor, a driver circuit, and a controller. The controller is configured to output a first control signal to control the motor to drive the drive structure to operate in a first operation mode for a preset period of time in response to receiving a start instruction. After the preset period of time, the controller will output a second control signal to control the motor to drive the drive structure to operate in a second operation mode to a preset state. The first operation mode and the second operation mode are two opposite operation modes.

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.

Disclosed herein are safety and other controls for chain saws, feedback for use with chain saws, cutting variations in chain saws, and accessories for use with chain saws. In one example, a system comprises a chain saw, a sensor for detecting a condition, and a control system programmed to take an action upon detection of a programmed condition. The chain saw may comprise links with engaging hooks and recesses for articulation without decoupling. The saw bar may comprise a rail, and the links may have grooves such that the links straddle the rail. In one example, a sensor may comprise an image sensor, and a condition detected by the sensor may comprise a position of the chain saw. The control system may be programmed to take action such as to stop or direct movement of the chain saw and/or to produce a perceptible signal.