Rotary hammer

Patent metadata

Field	Value
Publication number	US-9873192-B2
Application number	US-201414560660-A
Country	US
Kind code	B2
Filing date	Dec 4, 2014
Priority date	Dec 11, 2013
Publication date	Jan 23, 2018
Grant date	Jan 23, 2018

Abstract

According to an aspect of the present invention there is provided a rotary hammer comprising an electric motor having its longitudinal axis perpendicular to the axis of the hammer spindle and the tool holder. A single switching arrangement activates and deactivates the hammer mechanism and the rotary drive mechanism for the tool holder. The switching arrangement has a cam portion acting on a coupling part to activate and deactivate the hammer drive mechanism, and acting on a slider part to engage and disengage a coupling sleeve with a drive sleeve to thereby activate and deactivate the rotary drive mechanism of the hammer spindle. The switching arrangement comprises a gear train disposed between the switching element and the cam portion.

First claim

The invention claimed is:

1. A rotary hammer comprising:
a hammer housing;
a motor having an armature shaft;
a hammer spindle rotatably mounted about a longitudinal axis in the hammer housing;
a tool holder provided at a front end of the hammer housing and being rotatingly driven by the motor about the longitudinal axis of the hammer spindle;
a hammer mechanism provided in the hammer housing for generating impacts acting on the rear end of a bit inserted into the tool holder, the hammer mechanism having a drive shaft able to be selectively coupled with the armature shaft; and
a switching arrangement for switching the rotary hammer between at least a pure drilling mode, a hammer drilling mode and a pure hammering mode, having a switching element rotatable from the outside of the hammer housing about a rotational axis, the switching arrangement having a cam portion for switching the rotary hammer between at least two modes of operation;
wherein the switching arrangement comprises a gear train disposed between the switching element and the cam portion,
wherein the switching arrangement further comprises a coupling part axially displaceable on the drive shaft of the hammer mechanism between a lower position in which the drive shaft is coupled to the armature shaft and an upper position in which the drive shaft is decoupled from the armature shaft, and a selector for displacing the coupling part between the lower position and the upper position.

2. The rotary hammer as claimed in claim 1 , wherein the gear train has a gear ratio which is less than 1.

3. The rotary hammer as claimed in claim 2 , wherein the gear ratio of the gear train is comprised between 0.5 and 0.9.

4. The rotary hammer as claimed in claim 1 , wherein the gear train comprises a first gear rigidly connected to the switching element and a second gear rigidly connected to the cam portion, the first and second gears being arranged to mesh with each other.

5. The rotary hammer as claimed in claim 1 , wherein the selector extends along an internal axis which is substantially perpendicular to the longitudinal axis of the hammer spindle and wherein the selector is rotatable about the internal axis.

6. The rotary hammer as claimed in claim 5 , comprising a lateral offset between the rotational axis of the switching element and the internal axis of the selector.

7. The rotary hammer as claimed in claims 1 , wherein the coupling part is formed with a sleeve comprising a flange and wherein the selector comprises a fork having two arms for engaging a lower part of the flange of the sleeve-shaped coupling part.

8. The rotary hammer as claimed in claim 1 , wherein the selector comprises a drive member and wherein the cam portion comprises a protuberance, the drive member and the protuberance being arranged so that the protuberance engages the drive member to pivot the selector when the switching element is rotated.

9. The rotary hammer as claimed in claim 8 , wherein the protuberance and the drive member are adapted such that the protuberance engages the drive member over only a portion of the rotational movement of the cam portion.

10. The rotary hammer as claimed in claim 1 , wherein the armature shaft of the motor is arranged substantially perpendicular to the axis of the hammer spindle, and drives a drive sleeve which is arranged rotatably on the hammer spindle and which can be coupled with the hammer spindle via a coupling sleeve which sits non-rotatably but axially displaceable on the hammer spindle.

11. The rotary hammer as claimed in claim 10 , wherein the cam portion of the switching arrangement acts on the coupling sleeve via a linear slider part which can be moved parallel to the longitudinal axis of the hammer splindle so that the coupling sleeve can be moved between a position of engagement with the drive sleeve and a release position separated from the drive sleeve.

Assignees

• Black & Decker Inc

Inventors

• Lauterwald Martin

Classifications

• B25D11/04

  in which the tool bit or anvil is hit by an impulse member · CPC title

• B25D2216/0015

  Tools having a percussion-only mode · CPC title

• B25D16/006 Primary

  Mode changers; Mechanisms connected thereto · CPC title

• B25D2216/0023

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

• B25D2211/003

  Crossed drill and motor spindles · CPC title