Abstract: A robotic work tool system (200) comprising a boundary (230) enclosing a work area (205) and a robotic work tool (100) comprising a proximity sensor (180) arranged to sense an obstacle (S1, S2, O, B), the robotic work tool (100) being arranged to operate within the work area (205) and the robotic work tool (100) being configured to determine (610) a sensed obstacle (S1, S2, O, B); determine (620) a distance (d); determine (630) whether the distance (d) is inside a threshold distance (D), and if so disregard (640) the proximity sensor (180); and, if not, take (650) evasive action to avoid the sensed obstacle (S1, S2, O, B).

Abstract: A robotic work tool system (200) comprising a robotic worktool (100) comprising a distance sensor (190, 190?, 190?), the robotic work tool (100) being configured to determine a sensed distance (SD) to a surface travelled (G); determine whether the sensed distance is greater than a threshold distance; and if so detect a lift event.

Abstract: A robotic working tool system (200) comprising a base station (210) comprising a signal generator (240), a wire (230) and a robotic working tool (100) comprising at least one wire sensor (170), the robotic working tool system (200) being configured for: generating a detection signal (235) in the signal generator (240); transmitting the detection signal (235) through the wire (230); detecting a break in the wire by detecting that the detection signal is not detectable; and in response thereto emitting an alert.

Abstract: A robotic work tool system (200) for defining a working area (205) in which a robotic work tool (100) is subsequently intended to operate. The robotic work tool system (200) comprises a robotic work tool (100), at least one controller (210) and at least one memory (220). The robotic work tool (100) comprises at least one sensor unit (170) configured to collect sensed input datawhile the robotic work tool (100) is driven around the working area (205) to preliminarily define a perimeter around the working area (205). The at least one controller (210) is configured to establish a preliminary working area perimeter (250). The at least one memory (220) is configured to store a perimeter adjustment function and instructions that cause the at least one controller (210) to adjust the perimeter of the working area (205) by applying the stored perimeter adjustment function to the established preliminary working area perimeter (250)and thereby produce an adjusted working area perimeter (260).

Abstract: A variable timing system for a sewing machine is provided comprising a shuttle hook having a hook tip, a first helical gear mounted on the shuttle hook, a lower shaft configured to rotate the shuttle hook in synchronization with a needle bar, and a second helical gear mounted on the lower shaft and capable of engaging with the first helical gear. In accordance with embodiments, at least one of the helical gears is axially movable. The variable timing system may comprise a control device configured to generate a control signal representative of a current sewing situation. A drive force mechanism may receive the control signal and in response, transmit axial movement to the axially moveable helical gear to move the gear into proper position relative to a threaded needle of the sewing machine.

Abstract: A variable timing system for a sewing machine is provided comprising a shuttle hook having a hook tip, a first helical gear mounted on the shuttle hook, a lower shaft configured to rotate the shuttle hook in synchronization with a needle bar, and a second helical gear mounted on the lower shaft and capable of engaging with the first helical gear. In accordance with embodiments, at least one of the helical gears is axially movable. The variable timing system may comprise a control device configured to generate a control signal representative of a current sewing situation. A drive force mechanism may receive the control signal and in response, transmit axial movement to the axially moveable helical gear to move the gear into proper position relative to a threaded needle of the sewing machine.