Hammer drill

Patent metadata

Field	Value
Publication number	US-11052525-B2
Application number	US-201715421118-A
Country	US
Kind code	B2
Filing date	Jan 31, 2017
Priority date	Mar 3, 2016
Publication date	Jul 6, 2021
Grant date	Jul 6, 2021

Abstract

A hammer drill includes a housing, a tool holder, a hammering member, a gear, and a conversion member. The gear is switched to a first state where a rotation of the intermediate shaft is transmitted and a second state where the rotation of the intermediate shaft is not transmitted, and a mode switching member is configured to perform a switching operation of the state of the gear from an outside of the housing. The switching of the state of the gear by the mode switching member provides at least two operation modes of a hammer drill mode where the gear integrally rotates with the intermediate shaft to generate the rotation and a reciprocation of the hammering member on the tool holder and a hammer mode where the gear is separated from the rotation of the intermediate shaft to generate only the reciprocation of the hammering member.

First claim

What is claimed is:

1. A hammer drill comprising:
a housing configured to house a motor;
a tool holder configured to hold a tool bit, the tool holder being disposed in the housing and configured such that an entirety of the tool holder is movable back and forth between a front position and a rear position in the housing;
a hammering member disposed movable back and forth inside the tool holder;
an intermediate shaft disposed parallel to the tool holder inside the housing, a rotation of the motor being transmitted to the intermediate shaft to cause rotation of the intermediate shaft;
a gear disposed on the intermediate shaft, the gear selectively transmitting the rotation of the intermediate shaft to the tool holder to cause rotation of the tool holder; and
a conversion member disposed on the intermediate shaft, the conversion member converting the rotation of the intermediate shaft to a reciprocation of the hammering member, wherein:
the gear is configured to be switched to a first state where the rotation of the intermediate shaft is transmitted to the tool holder and a second state where the rotation of the intermediate shaft is not transmitted to the tool holder, and a mode switching member is configured to perform a switching operation of the gear between the first state and the second state from an outside of the housing;
switching of the gear by the mode switching member between the first state and the second state provides at least two operation modes of (1) a hammer drill mode where the gear integrally rotates with the intermediate shaft to generate the rotation of the tool holder and the reciprocation of the hammering member and (2) a hammer mode where the gear is separated from the rotation of the intermediate shaft to generate only the reciprocation of the hammering member;

the entirety of the tool holder is movable to the rear position only when the hammer mode and the hammer drill mode are alternatively selected; and
the entirety of the tool holder is not movable and cannot be moved to the rear position when the hammer drill is in a mode other than the hammer mode or the hammer drill mode.

2. The hammer drill according to claim 1 , wherein
the gear is configured to slide between an engaging position where the gear engages with the intermediate shaft to integrally rotate and a non-engaging position where the gear does not engage the intermediate shaft so as to switch the gear between the first state and the second state.

3. The hammer drill according to claim 2 , further comprising
a clutch disposed on the intermediate shaft integrally rotatable and slidable in an axial direction, the clutch being configured to move back and forth when the tool holder is moved back and forth so as to engage with and disengage from the conversion member, wherein
the mode switching member is configured to switch the clutch to a meshing position where the clutch meshes with the conversion member to integrally rotate and a non-meshing position where the clutch does not mesh with the conversion member, and
when the gear is in the engaging position and the clutch is in the non-meshing position, the hammer drill is in a drill mode in which the tool holder is rotated.

4. The hammer drill according to claim 3 , wherein;
the conversion member and the clutch engage such that a convex portion disposed on one of the conversion member and the clutch and a depressed portion disposed on another of the conversion member and the clutch mesh in a rotation direction,
meshing surfaces of the convex portion and the depressed portion each have a shape such that the one of the conversion member and the clutch is further displaced to the side when meshing with the another of the conversion member and the clutch in the rotation direction on distal end side contact points, and
in a state where the convex portion and the depressed portion mesh with one another, the meshing surfaces interfere to generate a resistance in a separating direction of the conversion member and the clutch.

5. The hammer drill according to claim 2 , wherein
a rotation restricting unit is disposed to selectively restrict rotation of the gear.

6. The hammer drill according to claim 5 , wherein
the rotation restricting unit includes a support pin disposed upright from an inner surface of the housing parallel to the intermediate shaft, a locking member penetrated and supported by the support pin to mesh with the gear, and a coil spring that biases the locking member to a meshing position with the gear.

7. The hammer drill according to claim 2 , wherein
the housing includes an internal guide shaft supported parallel to the intermediate shaft, a sliding member configured to lock on the gear to move back and forth along the guide shaft, and a biasing unit that biases the sliding member to the engaging position of the gear, and the sliding member moves in an opposite direction to a biasing direction of the biasing unit in accordance with operation of the mode switching member, such that the gear slides to the non-engaging position.

8. The hammer drill according to claim 7 , wherein
the sliding member is disposed on a side of the intermediate shaft.

9. The hammer drill according to claim 7 , wherein
the housing includes an internal inner housing configured to support a rear end of the intermediate shaft, and the inner housing includes a stopper portion with which the sliding member is brought in contact so as to restrict a retreat of the sliding member.

10. The hammer drill according to claim 7 , wherein
the mode switching member includes two eccentric pins to perform a rotating operation, and one of the two eccentric pins is configured to move the sliding member in an opposite direction to the biasing direction in accordance with the rotating operation.

11. The hammer drill according to claim 2 , wherein
the intermediate shaft has an end portion having a small diameter compared with an installation side of the conversion member, and the gear is externally installed on the end portion such that the gear engages with an engaging portion disposed on a base of the end portion to integrally rotate with the intermediate shaft.

12. The hammer drill according to claim 11 , wherein
the end portion has a front portion on which an O-ring is externally installed to retain the gear.

13. The hammer drill according to claim 1 , wherein
the motor is disposed below the intermediate shaft inside the housing, and a handlebar is disposed on a rear of the tool holder.

14. The hammer drill according to claim 1 , wherein the hammer drill operates in hammer mode or the hammer drill mode when the tool holder is in the rear position, but not when the tool holder is in the front position.

15. The hammer drill according to claim 1 , wherein the hammer drill operates in a drill only mode when the tool holder is in the front position.

16. The hammer drill according to claim 1 , wherein when the hammer mode and the hammer drill mode are alternatively implemented, the tool holder is in the rear position.

17. A hammer drill comprising:
a housing configured to house a motor;
a tool holder configured to hold a tool bit, the tool holder being disposed in the housing and configured such that an entirety of the tool holder is movable back and forth between a front position and a rear position in the housing;
a hammering member disposed movable back and forth inside the tool holder;
an intermediate shaft disposed parallel to the tool holder inside the housing, a rotation of the motor being transmitted to the intermediate shaft

Assignees

• Makita Corp

Inventors

• Furusawa Masanori
• Mori Keita
• Tada Yoshiro

Classifications

• B25D2211/003

  Crossed drill and motor spindles · CPC title

• B25D2216/0038

  Tools having a rotation-only mode · CPC title

• B25D2216/0015

  Tools having a percussion-only mode · CPC title

• B25D2211/061

  Swash-plate actuated impulse-driving mechanisms · CPC title

• B25D2216/0023

  Tools having a percussion-and-rotation mode · CPC title