Abstract: An illuminator that emits light from a radially outer portion of the cutting tool toward the cutting tool includes a first light source and a second light source, and a first lens and a second lens. The first lens has a first emission surface including a first outermost portion located farthest and at a first distance from a first center axis including a first light source center of the first light source and perpendicular to the first light source. The second lens has a second emission surface including a second outermost portion located farthest and at a second distance from a second center axis including a second light source center of the second light source and perpendicular to the second light source. A distance between the first center axis and the second center axis is shorter than a sum of the first distance and the second distance.

Abstract: An illuminator that emits light from a radially outer portion of the cutting tool toward the cutting tool includes a first light source and a second light source, and a first lens and a second lens. The first lens has a first emission surface including a first outermost portion located farthest and at a first distance from a first center axis including a first light source center of the first light source and perpendicular to the first light source. The second lens has a second emission surface including a second outermost portion located farthest and at a second distance from a second center axis including a second light source center of the second light source and perpendicular to the second light source. A distance between the first center axis and the second center axis is shorter than a sum of the first distance and the second distance.

Abstract: A lever device is configured such that, when first and second plates are relatively moved in a direction in which a second end part of the first plate and a fourth end part of the second plate are close to each other from a state in which the second end part and the fourth end part are separated from each other in an axial direction of a bolt, the first plate is rotated around a fulcrum positioned between a first engagement part and the second end part in the crossing direction so that the first plate is moved from an engaged position where the first engagement part and a non-circular part of the bolt or a nut are engaged to a non-engaged position where they are not engaged, and thereby removing a restriction of the relative rotation of the first plate to the non-circular part.

Abstract: A lever device is configured such that, when first and second plates are relatively moved in a direction in which a second end part of the first plate and a fourth end part of the second plate are close to each other from a state in which the second end part and the fourth end part are separated from each other in an axial direction of a bolt, the first plate is rotated around a fulcrum positioned between a first engagement part and the second end part in the crossing direction so that the first plate is moved from an engaged position where the first engagement part and a non-circular part of the bolt or a nut are engaged to a non-engaged position where they are not engaged, and thereby removing a restriction of the relative rotation of the first plate to the non-circular part.