Striking tool

1. A striking tool, comprising:

a housing including a supply port;

a striking mechanism in the housing, the striking mechanism including

a striker movable back and forth in a striking axis direction, and

a piston configured to move the striker back and forth;

a crank mechanism in the housing, the crank mechanism including

a crank shaft rotatable when driven by a motor, and

an eccentric pin on the crank shaft, the eccentric pin being movable eccentrically;

a cap attached to the supply port in a removable manner;

a first counterweight in the housing at a position at which the cap closes the supply port, the first counterweight having an elongated hole (1) extending perpendicular to the striking axis direction and (2) that receives a member that causes movement of the first counterweight relative to the housing, the first counterweight being movable in cooperation with the crank mechanism, and being configured to reduce vibrations in the striking axis direction resulting from the piston that is reciprocating; and

a second counterweight in the housing at a position at which the cap closes the supply port, the second counterweight being rotatable in cooperation with the crank mechanism, and being configured to reduce vibrations in a rotational direction resulting from the crank shaft;

wherein the first counterweight is slidable in the striking axis direction but is not rotatable relative to the housing.

2. The striking tool according to claim 1 , wherein

the crank mechanism converts rotation of the crank shaft into reciprocation of the piston.

3. The striking tool according to claim 2 , further comprising:

a connecting rod connecting the eccentric pin and the piston.

4. The striking tool according to claim 2 , wherein

the first counterweight operates at a position corresponding to a position of the eccentric pin advanced in a direction of an eccentric motion from a reference position of the eccentric pin at which the piston reaches a dead center.

5. The striking tool according to claim 2 , wherein

the striking mechanism includes a cylinder accommodating the piston, and

the first counterweight is movable back and forth in the striking axis direction and at least partially overlaps the cylinder in the striking axis direction.

6. The striking tool according to claim 2 , further comprising:

a bearing axially supporting the second counterweight,

wherein the second counterweight and the bearing are mounted on the cap.

7. The striking tool according to claim 1 , further comprising:

a connecting rod connecting the eccentric pin and the piston.

8. The striking tool according to claim 7 , wherein

the first counterweight operates at a position corresponding to a position of the eccentric pin advanced in a direction of an eccentric motion from a reference position of the eccentric pin at which the piston reaches a dead center.

9. The striking tool according to claim 7 , wherein

the striking mechanism includes a cylinder accommodating the piston, and

the first counterweight is movable back and forth in the striking axis direction and at least partially overlaps the cylinder in the striking axis direction.

10. The striking tool according to claim 7 , further comprising:

a bearing axially supporting the second counterweight,

wherein the second counterweight and the bearing are mounted on the cap.

11. The striking tool according to claim 1 , wherein

the first counterweight operates at a position corresponding to a position of the eccentric pin advanced in a direction of an eccentric motion from a reference position of the eccentric pin at which the piston reaches a dead center.

12. The striking tool according to claim 11 , wherein

the striking mechanism includes a cylinder accommodating the piston, and

the first counterweight is movable back and forth in the striking axis direction and at least partially overlaps the cylinder in the striking axis direction.

13. The striking tool according to claim 11 , further comprising:

a bearing axially supporting the second counterweight,

wherein the second counterweight and the bearing are mounted on the cap.

14. The striking tool according to claim 1 , wherein

the striking mechanism includes a cylinder accommodating the piston, and

the first counterweight is movable back and forth in the striking axis direction and at least partially overlaps the cylinder in the striking axis direction.

15. The striking tool according to claim 1 , further comprising:

a bearing axially supporting the second counterweight,

wherein the second counterweight and the bearing are mounted on the cap.

16. A striking tool, comprising:

a housing including a supply port;

a striking mechanism in the housing, the striking mechanism including

a striker movable back and forth in a striking axis direction, and

a piston configured to move the striker back and forth;

a crank mechanism in the housing, the crank mechanism including

a crank shaft rotatable when driven by a motor, and

an eccentric pin on the crank shaft, the eccentric pin being movable eccentrically;

a cap attached to the supply port in a removable manner;

a first counterweight in the housing at a position at which the cap closes the supply port, the first counterweight being movable in cooperation with the crank mechanism, and being configured to reduce vibrations in the striking axis direction resulting from the piston that is reciprocating;

a second counterweight in the housing at a position at which the cap closes the supply port, the second counterweight being rotatable in cooperation with the crank mechanism, and being configured to reduce vibrations in a rotational direction resulting from the crank shaft; and

a bearing axially supporting the second counterweight, wherein:

the second counterweight and the bearing are mounted on the cap; and

the second counterweight includes an engageable portion engageable with the eccentric pin, rotates in cooperation with the eccentric pin, and is mounted on the cap.

17. A striking tool, comprising:

a housing including a supply port;

a striking mechanism in the housing, the striking mechanism including

a striker movable back and forth in a striking axis direction, and

a piston configured to move the striker back and forth;

a crank mechanism in the housing, the crank mechanism including

a crank shaft rotatable when driven by a motor, and

an eccentric pin on the crank shaft, the eccentric pin being movable eccentrically;

a cap attached to the supply port in a removable manner;

a first counterweight in the housing at a position at which the cap closes the supply port, the first counterweight being movable in cooperation with the crank mechanism, and being configured to reduce vibrations in the striking axis direction resulting from the piston that is reciprocating;

a second counterweight in the housing at a position at which the cap closes the supply port, the second counterweight being rotatable in cooperation with the crank mechanism, and being configured to reduce vibrations in a rotational direction resulting from the crank shaft, and

a bearing axially supporting the second counterweight, wherein:

the second counterweight and the bearing are mounted on the cap;

the second counterweight includes:

a rotatable member axially supported by the bearing and held in the cap in a rotatable manner; and

a connecting member engageable with the eccentric pin to receive rotation; and

at least one of the rotatable member or the connecting member includes a weight portion.

18. The striking tool according to claim 17 , wherein

the first counterweight is located between the rotatable member and the connecting member in a manner movable back and forth in the striking axis direction.

19. The striking tool according to claim 17 , wherein

the cap has an insertion opening through which an external separate member is insertable to directly or indirectly lock rotation of the connecting member.

20. The striking tool according to claim 19 , wherein

the insertion opening relieves pressure inside a crank chamber accommodating the crank mechanism.