Abstract: An oil supply structure of a chain saw comprises a pair of rail portions which are provided on the outer circumference of the main body of a guide plate, a guide groove which is formed between the two rail portions, a pair of oil supply holes which penetrate the two rail portions from outside and which open toward the guide groove, a through hole which penetrates the main body of the guide plate without any connection with the guide groove, and a pair of connection channels which connect outer end openings of each oil supply hole and two outer end openings of the through hole. Lubricating oil is supplied from an outlet port of the main body of the chain saw to both sides of a saw chain and so forth through the through hole, connection channel and oil supply hole.

Abstract: A cutting head for a cord type mower which severs grass and weeds with cords unwound from a cord spool provided within a bowl-shaped rotary casing and radially projected from the rotary casing by rotating the rotary casing at a high rotating speed. A speed change control mechanism is provided within the rotary casing to control the rotating speed of the rotary casing so as to vary it according to the length of the projecting portions of the cords. When the cords wear and shorten, the moment of inertia of the cutting head decreases; consequently the rotating speed of the rotary casing increases and thereby the cords are fed out automatically by the increased centrifugal force acting on the cords. Then, the engaging members members engaging the speed change control plate are moved radially outward by the centrifugal force to reduce the rotating speed of the rotary casing. Thus, the cords are always projected by a predetermined length from the rotary casing for stable mowing operation.