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.

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.

A lift apparatus is provided for use with a vehicle comprising a first frame and a second frame. The lift apparatus comprises a spindle, a bearing, a cylinder, a snap ring, and a bearing retainer. The spindle is configured to be attached to the second frame so as to extend therefrom in spaced apart relation to the first frame. The bearing is positioned on the spindle. The cylinder is configured to be attached to the first frame and is attached to the second frame to move the first frame relative to the second frame. The cylinder is positioned on the bearing such that the bearing enables movement between the spindle and the cylinder. The snap ring is attached to the spindle. The bearing retainer is positioned on the spindle between the snap ring, and the bearing retains the bearing on the spindle.

A system and method for an autonomous lawn mower comprising a mower body having at least one motor arranged to drive a cutting blade and to propel the mower body on an operating surface via a wheel arrangement, wherein the mower body includes a navigation system arranged to assist a controller to control the operation of the mower body within a predefined operating area.

A system and method for an autonomous lawn mower comprising a mower body having at least one motor arranged to drive a cutting blade and to propel the mower body on an operating surface via a wheel arrangement, wherein the mower body includes a navigation system arranged to assist a controller to control the operation of the mower body within a predefined operating area.

Systems and techniques for detecting suboptimal mowing due to impacted vegetation and/or orientation changes are discussed. In some examples, blade speeds, blade heights, torques, and/or a current required to spin the blades of a mower at a determined rate may be calibrated and associated with a lawn mower and/or map. Changes in any one or more of the blade speed, current required, torque, etc. (and/or additional data from one or more sensors on the mower) may be used as an indication for determining whether vegetation has impacted the underside of a mower, whether the blade has struck an object, whether the mower is undergoing an orientation change, whether the mower requires maintenance, and the like. Based on the indication, the mower can perform one or more functions to attempt to remediate the problem autonomously and/or send a signal to a user for additional help.

Systems and techniques for detecting suboptimal mowing due to impacted vegetation and/or orientation changes are discussed. In some examples, blade speeds, blade heights, torques, and/or a current required to spin the blades of a mower at a determined rate may be calibrated and associated with a lawn mower and/or map. Changes in any one or more of the blade speed, current required, torque, etc. (and/or additional data from one or more sensors on the mower) may be used as an indication for determining whether vegetation has impacted the underside of a mower, whether the blade has struck an object, whether the mower is undergoing an orientation change, whether the mower requires maintenance, and the like. Based on the indication, the mower can perform one or more functions to attempt to remediate the problem autonomously and/or send a signal to a user for additional help.

The present disclosure relates to a lawn mower (100) comprising a cutter propulsion unit (165), a transmission axle (166, 166′) that has a longitudinal extension (L, L′) and is adapted to be rotated by the cutter propulsion unit (165). The lawn mower (100) further comprises a cutting disc (160) that has a radial extension (R) that runs between a center (182) and an outer edge (181), where the cutting disc (160) comprises one or more cutting edges (161, 162, 163) that are adapted to cut grass when the cutting disc (160) is brought into a rotational motion by means of the transmission axle (166). The cutting disc (160) further comprises a connection portion (164, 164′) which is adapted to receive a coupling member (173, 173′), comprised in the transmission axle (166, 166′), in at least two different mounting positions that are adapted to position the connection portion (164) in mutually separated positions along the longitudinal extension (L, L′).

One example provides a grinding positioning plate for a reel-type mower unit including a cutting reel having a rotational axis. The grinding positioning plate includes a main body including a pivot element having a pivot axis, and at least one pair of clamping assemblies, each clamping assembly to clamp to a corresponding mounting flange of the reel-type mower unit to mount the main body to reel-type mower unit such that the pivot axis is in parallel with the rotational axis and at a known horizontal distance from the rotational axis.

One example provides a grinding positioning plate for a reel-type mower unit including a cutting reel having a rotational axis. The grinding positioning plate includes a main body including a pivot element having a pivot axis, and at least one pair of clamping assemblies, each clamping assembly to clamp to a corresponding mounting flange of the reel-type mower unit to mount the main body to reel-type mower unit such that the pivot axis is in parallel with the rotational axis and at a known horizontal distance from the rotational axis.