Power tool having hammer mechanism

Patent metadata

Field	Value
Publication number	US-11529727-B2
Application number	US-202017072484-A
Country	US
Kind code	B2
Filing date	Oct 16, 2020
Priority date	Oct 21, 2019
Publication date	Dec 20, 2022
Grant date	Dec 20, 2022

Abstract

A power tool, such as a rotary hammer, includes a housing, an output shaft for mounting a tool accessary and a motor having a motor shaft that generates a rotational output for rotating and linearly hammering the output shaft. The rotational output of the motor shaft is coupled to the output shaft via a driving mechanism that includes a hammer mechanism. An intervening member is axially movable relative to the motor shaft and is operably coupled between the motor shaft and the hammer mechanism. The hammer mechanism and the output shaft are supported by a movable support that is axially movable relative to the housing. Because the output shaft and the driving mechanism are movable relative to the motor and the housing, which preferably includes handle, via the intervening member and the movable support during hammering operations, vibration generated during hammering operations can be dampened before reaching the housing.

First claim

What is claimed is:

1. A power tool, comprising:
a motor having a motor shaft;
a final output shaft configured to removably hold a tool accessory and having a driving axis;
a driving mechanism configured to selectively rotationally drive the tool accessory around the driving axis using power from the motor, the driving mechanism including a motion converting mechanism configured to selectively convert rotational motion into reciprocating linear motion that axially drives the tool accessory along the driving axis to perform a hammering operation;
a housing that houses the motor, the final output shaft and the driving mechanism;
a movable support that supports the final output shaft and the motion converting mechanism within the housing such that the movable support, the final output shaft and the motion converting mechanism are movable relative to the housing in parallel with the driving axis while being biased by at least one elastic member;
a first intermediate shaft supported to be immovable in an axial direction of the first intermediate shaft relative to the housing, the first intermediate shaft being configured to rotate around a first axis parallel to the driving axis in response to rotation of the motor shaft and to transmit power to the motion converting mechanism;
an intervening member disposed between the first intermediate shaft and the motion converting mechanism so as to be selectively rotatable relative to the first intermediate shaft around the first axis, the intervening member being immovable relative to the first intermediate shaft along the first axis; and
a transmitting member coupled to the first intermediate shaft such that the transmitting member rotates together with the first intermediate shaft;
wherein:
the transmitting member is movable relative to the first intermediate shaft along the first axis between an engagement position and a disengagement position,
in the engagement position, the transmitting member is engaged with the intervening member to thereby transmit power from the first intermediate shaft to the intervening member,
in the disengagement position, the transmitting member is disengaged from the intervening member such that power transmission from the first intermediate shaft to the intervening member is interrupted,
the motion converting mechanism includes a first portion that is coupled with the intervening member such that the intervening member and the first portion rotate together, and
the motion converting mechanism is movable together with the movable support relative to the intervening member in parallel with the driving axis.

2. The power tool as defined in claim 1 , wherein:
a spline part is provided on a portion of an outer periphery of the first intermediate shaft, and
the transmitting member is engaged with the spline part of the first intermediate shaft.

3. The power tool as defined in claim 1 , wherein:
a spline part is provided on at least a portion of an outer periphery of the intervening member, and
the first portion of the motion converting mechanism is engaged with the spline part of the intervening member such that the first portion of the motion converting mechanism and the intervening member rotate together and such that the motion converting mechanism is movable relative to the intervening member along the first axis.

4. The power tool as defined in claim 3 , wherein the transmitting member has a first spline part configured to be selectively engaged with the spline part of the intervening member.

5. The power tool as defined in claim 4 , wherein:
a spline part is provided on a portion of an outer periphery of the first intermediate shaft,
the transmitting member has a second spline part engaged with the spline part of the first intermediate shaft, and
the first spline part of the transmitting member has a larger diameter than the second spline part of the transmitting member.

6. The power tool as defined in claim 1 , wherein the transmitting member is biased toward the engagement position.

7. The power tool as defined in claim 1 , wherein:
a gap is formed between the first intermediate shaft and the intervening member in a radial direction of the first intermediate shaft, and
the gap is partially narrowed in the vicinity of the transmitting member.

8. The power tool as defined in claim 1 , wherein the intervening member is a circular cylindrical member disposed coaxially around the first intermediate shaft.

9. The power tool as defined in claim 1 , wherein the transmitting member is a circular cylindrical member disposed coaxially around the first intermediate shaft.

10. The power tool as defined in claim 1 , wherein:
the first portion of the motion converting mechanism is supported by the movable support so as to be rotatable around the first axis, and
the intervening member is supported such that the motion converting mechanism is movable relative to the intervening member along the first axis.

11. The power tool as defined in claim 10 , wherein:
the first portion of the motion-converting mechanism includes a rotary body that is spline-connected with the intervening member and is supported by the movable support so as to be rotatable around the first axis; and
the motion-converting mechanism further includes an oscillating member disposed around the rotary body and configured to oscillate in a direction parallel to the driving axis in response to rotation of the rotary body.

12. The power tool as defined in claim 1 , wherein:
the transmitting member and the intervening member form a first clutch mechanism configured to selectively transmit and interrupt power for the hammering operation,
the driving mechanism is configured to transmit rotational power for a drilling operation to the final output shaft either from the first intermediate shaft or from a second intermediate shaft that is spaced apart from the first intermediate shaft, and
the power tool further includes a second clutch mechanism provided on and/or around one of the first intermediate shaft or the second intermediate shaft and configured to selectively transmit and interrupt rotational power for the drilling operation.

13. The power tool as defined in claim 12 , further comprising:
a manually operable member configured to selectively change an action mode of the power tool,
wherein the first clutch mechanism and the second clutch mechanism are each configured to be switched between a power-transmission state and a power-interruption state in accordance with manual operation of the manually operable member.

14. The power tool as defined in claim 12 , wherein:
the first intermediate shaft is configured to transmit power only for performing the hammering operation and not the drilling operation,
the second intermediate shaft is configured to transmit power only for performing the drilling operation and not the hammering operation, and
the second clutch mechanism is provided on and/or around the second intermediate shaft.

15. The power tool as defined in claim 1 , further comprising:
at least one guide shaft extending within the housing parallel to the driving axis,
wherein the at least one guide shaft is inserted through at least one support hole provided in the movable support and is configured to guide movement of the movable support relative to the housing in parallel to the driving axis.

16. A power tool configured to linearly reciprocally drive a tool accessory along a driving axis to perform a hammering operation and to rotationally drive the tool accessory around the driving axis to perform a drilling operation

Assignees

• Makita Corp

Inventors

• Yoshikane Kiyonobu
• Machida Yoshitaka
• Iida Hitoshi
• Nakagawa Kazuki

Classifications

• B25D2216/0015

  Tools having a percussion-only mode · CPC title

• B25D2217/0073

  Arrangements for damping of the reaction force · CPC title

• B25D2216/0038

  Tools having a rotation-only mode · CPC title

• B25D11/062 Primary

  comprising a wobbling mechanism, swash plate · CPC title

• B25D2216/0046

  Preventing rotation · CPC title