Portable cutting machine
An operation member has a higher degree of design freedom in, for example, the position and the amount of displacement of an operation part, and the force used for operation. A portable cutting machine includes a base, an electric motor, a blade rotatable by the electric motor, a movable cover covering a lower part of the blade protruding downward from the base and rotatable to be open, an operation lever located frontward from a rotation center of the blade and rotatable, and a transmission lever rotatable to push and open the movable cover when pushed by the operation lever.
1. A portable cutting machine, comprising:
a base;
an electric motor supported by the base;
a blade rotatable by the electric motor and having a rotational axis;
a stationary cover covering an upper part of the blade;
a movable cover ( 1 ) covering a lower part of the blade protruding downward from the base in a closed position and ( 2 ) being rotatable to be opened from the closed position;
an operation lever ( 1 ) located frontward from a rotation center of the blade, ( 2 ) being rotatable and ( 3 ) configured to be operated by a hand of a user of the portable cutting machine; and
a rotatable transmission lever, wherein:
the rotatable transmission lever includes a rotation axis and a rotatable arm extending from and rotatable around the rotation axis;
the operation lever includes
an operation arm, and
an output arm shorter than the operation arm;
the output arm is configured such that the output arm pushes and rotates the rotatable transmission lever when the operation lever is rotated in a first direction;
the operation lever includes a shaft extending through the stationary cover;
the operation arm is connected to the shaft outside the stationary cover along the rotational axis of the blade;
the output arm is connected to the shaft inside the stationary cover along the rotational axis of the blade; and
the operation lever, the rotatable transmission lever and the movable cover are configured such that:
when the operation lever is rotated in a first direction, the operation lever contacts and rotates the rotatable arm of the rotatable transmission lever and rotation of the rotatable arm of the rotatable transmission lever moves the movable cover from the closed position to be opened; and
a distance from the rotation axis of the rotatable transmission lever to a contact point between the operation lever and the rotatable arm of the rotatable transmission lever decreases as a distance the movable cover moves from the closed position increases.
2. The portable cutting machine according to claim 1 , wherein
the rotation axis of the rotatable transmission lever is rearward from a rotation center of the operation lever.
3. The portable cutting machine according to claim 2 , wherein
the rotatable transmission lever and the operation lever are configured such that the rotatable transmission lever has a smaller rotation angle than a rotation angle of the operation lever when the operation lever and the rotatable transmission lever are operated to open the movable cover.
4. The portable cutting machine according to claim 1 , wherein
the rotatable arm includes
a front extension extending frontward from the rotation axis of the rotatable transmission lever, and
a downward extension extending downward from a distal end of the front extension, and
the rotatable transmission lever and the movable cover are configured such that the rotatable transmission lever pushes the movable cover with a distal end of the downward extension to open the movable cover.
5. The portable cutting machine according to claim 4 , wherein
the operation lever and the rotatable transmission lever are configured such that the operation lever pushes a front face of the downward extension to rotate the rotatable transmission lever.
6. The portable cutting machine according to claim 1 , wherein
the rotatable transmission lever and the operation lever are configured such that the rotatable transmission lever has a smaller rotation angle than a rotation angle of the operation lever when the operation lever and the rotatable transmission lever are rotated to open the movable cover.
7. The portable cutting machine according to claim 1 , wherein
the operation lever, the rotatable transmission lever and the movable cover are configured such that the operation lever, the rotatable transmission lever and the movable cover rotate in the same direction to open the movable cover.
8. The portable cutting machine according to claim 1 , wherein
the movable cover and the rotatable transmission lever are configured such that a distance from a rotation center of the movable cover to a contact between the movable cover and the rotatable transmission lever decreases as the distance the movable cover moves from the closed position increases.
9. The portable cutting machine according to claim 1 , wherein
the movable cover and the rotatable transmission lever are configured such that a contact between the rotatable transmission lever and the movable cover moves rearward as the distance the movable cover moves from the closed position increases.
10. The portable cutting machine according to claim 1 , wherein
the stationary cover includes a stopper, and
the rotatable transmission lever, the movable cover and the stopper are configured such that the rotatable transmission lever is out of contact with the movable cover when the movable cover is at a closed position determined by contact of the movable cover and the stopper.
11. The portable cutting machine according to claim 1 , wherein
the rotatable transmission lever includes a slider comprising a synthetic resin, and
the rotatable transmission lever and the movable cover are configured such that the slider slides on the movable cover when the rotatable transmission lever pushes the movable cover.
12. The portable cutting machine according to claim 11 , wherein
the slider comprises a polyacetal resin.
13. The portable cutting machine according to claim 1 , wherein
the operation lever includes a cylindrical member having a side surface configured to contact the rotatable transmission lever.
14. The portable cutting machine according to claim 1 , wherein
the operation lever includes a rolling member, and
the operation lever and the rotatable transmission lever are configured such that the rolling member rolls over the rotatable transmission lever when the operation lever pushes the rotatable transmission lever.