A lawn mower includes: a blade disk rotatable about a rotation shaft extending in an up-down direction; and a plurality of cutter blades mounted on the blade disk. The blade disk includes a plurality of blade mounting sections having corresponding ones of the cutter blades mounted thereon, and a circumferential high-rigidity section for increasing rigidity of the blade disk between the blade mounting sections. The blade mounting sections are located on, and spaced from each other along, an imaginary reference circle concentric with a rotation center of the blade disk, and the circumferential high-rigidity section is located in such a manner as to interconnect the plurality of blade mounting sections along the reference circle, the circumferential high-rigidity section being formed in a generally concave-convex configuration by being depressed and protruded in a facewise direction of the blade disk.

A low-energy blade system having a quick-change attachment for a lawn maintenance tool is provided. The low-energy blade system requires a reduced amount of energy to rotate the blade system. The blade system includes a shell, a mounting plate attached to the shell, a plurality of quick-attach mechanisms, and a separate cutting blade attachable to each of the quick-attach mechanisms. Each quick-attach mechanism allows a cutting blade to be attached to the mounting plate without the need for external tools, such as screwdriver, wrench, ratchet, or the like.

A quick connect mower blade system includes a blade bolt inserted into the top end of a hollow spindle and threaded into a collet having an upright inserted into the lower end of the spindle. The collet has a head that is aligned substantially perpendicular to a hole in a blade holder if the blade bolt is tightened onto the collet to clamp a mower blade between the spindle and blade holder.

A rotary vegetation cutting unit having: a frame having a drive shaft; at least one cutting element that moves with the frame; and a debris blocking assembly on the frame with a unitary part that moves relative to the frame in opposite directions around an operating axis. The unitary part is configured to deflect away from the at least one cutting element objects approaching the at least one cutting element in a radial direction. The rotary vegetation cutting unit further has a bearing assembly including: a) a bearing that guides movement between the unitary part and the shaft; and b) a holder for the bearing. The rotary vegetation cutting unit is configured so that any debris spaced radially from the rotary vegetation cutting unit is required to traverse a non-straight path to contact the bearing.

The mower blade system provides one or more blades, preferably two, secured to a housing that is attached to the mower. The blades provide a cutting edge that is sharpened for mowing the yard, lawn, field, or other area. The blade attaches to an attachment arm via a locking body and retention body. A pivot aperture of the blade is placed upon a pivot finger of the attachment arm that secures the blade on the attachment arm. The locking body abuts the pivot finger to secure the blade on the pivot finger. The retention body then slides over the locking body to further secure the blade on the pivot finger.

A cutter assembly has a crossbar, cutter blades, and blade pins. The crossbar defines bar openings. Each cutter blade defines a blade bolt opening and first and second blade edges. The blade pins are each adapted to be inserted through one of the bar openings and one of the blade bolt openings such that the head portions of the blade pins are within one of blade recesses of the cutter blades. Bolt key surfaces of the blade pins engage bar key surfaces of the crossbar to prevent rotation of the blade pins relative to the crossbar. The cutter blades are each operable in first and second configurations, where the first blade edges are in a leading position in the first configuration and the second blade edges are in a leading position in the second configuration.

A multi-mode trimmer head for use with an outdoor handheld tool such as a string trimmer, brush cutter, or the like is provided. The trimmer head includes an upper housing, lower housing, bump head, spool, and a spring. The spool includes a first pair of apertures configured to receive a pair of flexible trimmer lines to provide a bump-feed operating mode for the trimmer head. The spool also includes a separate, second pair of apertures configured to receive a single fixed-line trimmer line to provide a fixed-line operating mode for the trimmer head. The trimmer head is switchable between the fixed-line operating mode and the bump-feed operating mode without the need to disassemble the trimmer head.

A lawn care device may include a cutting deck housing at least one blade, a rotatable shaft, and a blade mount operably coupled to the rotatable shaft. The blade mount may include a clasp to secure the at least one blade within an engagement slot of the blade mount. The cover assembly may form a cavity with at least one sidewall extending substantially around a periphery of the blade mount.

A grass cutting mobile robot includes a body and a blade assembly connected to the body and rotatable about a drive axis. The blade assembly includes blades, a housing to hold the blades, and a spring that connects the blade to the housing. The housing includes a slot in which to mount a blade so that a portion of the blade is movable through the slot towards another blade in response to an impact. The slot slopes upwards in the housing towards the body, thereby enabling the blade to move upwards relative to a ground surface toward the body in response to the impact. The spring is for constraining movement of the blade relative to the housing.

The invention relates to a method for sawing a long profile (3) in that a sawing disc (2) having teeth (6) arranged around a circular outer circumference of the sawing disc (2) is rotated freely, the sawing disc (2) is advanced from a freely rotating position to an outer wall of the long profile (3), and a zero tooth (Z.sub.1, Z.sub.2, Z.sub.3, Z.sub.4) engages as the first of the teeth (6) in the material of the outer wall, wherein, during the free rotation of the sawing disc (2), lateral runouts (d) of the teeth (6) are determined, and a tooth (6) having a minimum lateral runout (d) is determined and used as the zero tooth (Z.sub.1, Z.sub.2, Z.sub.3, Z.sub.4).