Hammer drill having switching mechanism for switching operation modes

A hammer drill comprising:

• a housing;
• a motor disposed in the housing and generating a rotational force;
• a working tool;
• a striking force transmitting mechanism comprising:
• a cylinder rotatably supported in the housing, the cylinder extending in an axial direction and having a first end and a second end, the working tool being engaged with the first end so as to be rotatable together with the cylinder, the working tool being movable in the axial direction;
• a piston disposed adjacent to the second end in the cylinder and movable in a reciprocating motion in the axial direction;
• a motion converting mechanism that converts the rotational force of the motor into the reciprocating motion of the piston;
• and
• a striking member disposed between the working tool and the piston in the cylinder and slidable in the axial direction, an air chamber being formed in the cylinder between the piston and the striking member, the cylinder being formed with at least one through-hole for providing fluid communication between the air chamber and an outside of the cylinder;
• a rotational force transmitting mechanism comprising a gear that transmits the rotational force of the motor to the cylinder, thereby rotating the cylinder together with the working tool;
• and
• a switching mechanism that switches operation modes between:
• a first operation mode in which the at least one through-hole is closed when the working tool is moved toward the second end and, when the at least one through-hole is closed, the reciprocating motion of the piston generates pressure changes in the air chamber, allowing the striking member to transmit a striking force to the working tool;
• a second operation mode in which the at least one through-hole is constantly open, prohibiting the striking member from transmitting a striking force to the working tool;
• and
• wherein the switching mechanism switches the operation modes by restricting an amount of movement of the working tool toward the second end.

A hammer drill comprising:

• a housing;
• a motor disposed in the housing and generating a rotational force;
• a working tool;
• a striking force transmitting mechanism comprising:
• a cylinder rotatably supported in the housing, the cylinder extending in an axial direction and having a first end and a second end, the working tool being engaged with the first end so as to be rotatable together with the cylinder, the working tool being movable in the axial direction;
• a piston disposed adjacent to the second end in the cylinder and movable in a reciprocating motion in the axial direction;
• a motion converting mechanism that converts the rotational force of the motor into the reciprocating motion of the piston;
• and
• a striking member disposed between the working tool and the piston in the cylinder and slidable in the axial direction, an air chamber being formed in the cylinder between the piston and the striking member, the cylinder being formed with at least one through-hole for providing fluid communication between the air chamber and an outside of the cylinder;
• a rotational force transmitting mechanism comprising a gear that transmits the rotational force of the motor to the cylinder, thereby rotating the cylinder together with the working tool;
• and
• a switching mechanism that switches operation modes between:
• a first operation mode in which the at least one through-hole is closed when the working tool is moved toward the second end and, when the at least one through-hole is closed, the reciprocating motion of the piston generates pressure changes in the air chamber, allowing the striking member to transmit a striking force to the working tool;
• a second operation mode in which the at least one through-hole is constantly open, prohibiting the striking member from transmitting a striking force to the working tool;
• wherein the cylinder is movable in the axial direction when the working tool is moved toward the second end;
• and
• wherein the switching mechanism switches the operation modes by restricting an amount of movement of the cylinder.

A hammer drill comprising:

• a housing;
• a motor disposed in the housing and generating a rotational force;
• a working tool;
• a striking force transmitting mechanism comprising:
• a cylinder rotatably supported in the housing, the cylinder extending in an axial direction and having a first end and a second end, the working tool being engaged with the first end so as to be rotatable together with the cylinder, the working tool being movable in the axial direction;
• a piston disposed adjacent to the second end in the cylinder and movable in a reciprocating motion in the axial direction;
• a motion converting mechanism that converts the rotational force of the motor into the reciprocating motion of the piston;
• and
• a striking member disposed between the working tool and the piston in the cylinder and slidable in the axial direction, an air chamber being formed in the cylinder between the piston and the striking member, the cylinder being formed with at least one through-hole for providing fluid communication between the air chamber and an outside of the cylinder;
• a rotational force transmitting mechanism comprising a gear that transmits the rotational force of the motor to the cylinder, thereby rotating the cylinder together with the working tool;
• and
• switching mechanism that switches operation modes between:
• a first operation mode in which the at least one through-hole is closed when the working tool is moved toward the second end and, when the at least one through-hole is closed, the reciprocating motion of the piston generates pressure changes in the air chamber, allowing the striking member to transmit a striking force to the working tool;
• a second operation mode in which the at least one through-hole is constantly open, prohibiting the striking member from transmitting a striking force to the working tool;
• wherein the cylinder is movable in the axial direction when the working tool is moved toward the second end;
• and
• wherein the switching mechanism switches the operation modes by restricting an amount of movement of the cylinder.

A hammer drill comprising:

• a housing;
• a motor disposed in the housing and generating a rotational force;
• a working tool;
• a striking force transmitting mechanism comprising:
• a cylinder rotatably supported in the housing, the cylinder extending in an axial direction and having a first end and a second end, the working tool being engaged with the first end so as to be rotatable together with the cylinder, the working tool being movable in the axial direction;
• a piston disposed adjacent to the second end in the cylinder and movable in a reciprocating motion in the axial direction;
• a motion converting mechanism that converts the rotational force of the motor into the reciprocating motion of the piston;
• and
• a striking member disposed between the working tool and the piston in the cylinder and slidable in the axial direction, an air chamber being formed in the cylinder between the piston and the striking member, the cylinder being formed with at least one through-hole for providing fluid communication between the air chamber and an outside of the cylinder;
• a rotational force transmitting mechanism comprising a gear that transmits the rotational force of the motor to the cylinder, thereby rotating the cylinder together with the working tool;
• and
• a switching mechanism that switches operation modes between:
• a first operation mode in which the at least one through-hole is closed when the working tool is moved toward the second end and, when the at least one through-hole is closed, the reciprocating motion of the piston generates pressure changes in the air chamber, allowing the striking member to transmit a striking force to the working tool;
• and
• a second operation mode in which the at least one through-hole is constantly open, prohibiting the striking member from transmitting a striking force to the working tool;
• and
• wherein the switching mechanism is capable of switching the operation mode to a third operation mode in which transmission of the rotational force to the cylinder is turned off.

A hammer drill comprising:

• a housing;
• a motor disposed in the housing and generating a rotational force;
• a working tool;
• a striking force transmitting mechanism comprising:
• a cylinder rotatably supported in the housing, the cylinder extending in an axial direction and having a first end and a second end, the working tool being engaged with the first end so as to be rotatable together with the cylinder, the working tool being movable in the axial direction;
• a piston disposed adjacent to the second end in the cylinder and movable in a reciprocating motion in the axial direction;
• a motion converting mechanism that converts the rotational force of the motor into the reciprocating motion of the piston;
• and
• a striking member disposed between the working tool and the piston in the cylinder and slidable in the axial direction, an air chamber being formed in the cylinder between the piston and the striking member, the cylinder being formed with at least one through-hole for providing fluid communication between the air chamber and an outside of the cylinder;
• a rotational force transmitting mechanism comprising a gear that transmits the rotational force of the motor to the cylinder, thereby rotating the cylinder together with the working tool;
• and
• a switching mechanism that switches operation modes between:
• a first operation mode in which the at least one through-hole is closed when the working tool is moved toward the second end and, when the at least one through-hole is closed, the reciprocating motion of the piston generates pressure changes in the air chamber, allowing the striking member to transmit a striking force to the working tool;
• and
• a second operation mode in which the at least one through-hole is constantly open, prohibiting the striking member from transmitting a striking force to the working tool;
• wherein the cylinder has an outer peripheral surface;
• wherein the gear is rotatably supported around the outer peripheral surface of the cylinder;
• wherein the rotational force transmitting mechanism further comprises a coupling member disposed around the outer peripheral surface of the cylinder, the coupling member being fitted with the outer peripheral surface of the cylinder by spline fitting, allowing the coupling member to be slidable in the axial direction for engaging with and disengaging from the gear;
• and
• wherein the switching mechanism comprises a switching member that can be operated at least among a first switch position in which the coupling member is engaged with the gear and a second switch position in which the coupling member is disengaged from the gear.