Hand-held power tool and control method therefor

Patent metadata

Field	Value
Publication number	US-10369686-B2
Application number	US-201515532632-A
Country	US
Kind code	B2
Filing date	Dec 1, 2015
Priority date	Dec 3, 2014
Publication date	Aug 6, 2019
Grant date	Aug 6, 2019

Abstract

A hand-held power tool has a tool holder for holding a tool along a working axis. A hammer mechanism has a striker that is moved periodically at an impact rate along the working axis between a turning point in the proximity of the tool and a turning point remote from the tool. A drive control of the hammer mechanism sets the impact rate to a set point value. A vibration absorber has an oscillator that moves along the working axis about a resting position and one or multiple springs that drive the oscillator back into the resting position. A first sensor is used to determine a phase of the motion of the striker. A sensor is used to determine a first phase of a compression point of the hammer mechanism. Another sensor is used to determine a second phase of a turning point in the proximity of the tool, of the hammer mechanism. A damping controller adapts the set point value in such a way that a phase difference between the first phase and the second phase is less than a threshold value.

First claim

What is claimed is:

1. A hand-held power tool comprising:
a tool holder for holding a tool on a working axis;
a hammer mechanism including a striker moved periodically at an impact rate on the working axis between a turning point close to the tool and a turning point remote from the tool;
a drive control of the hammer mechanism setting the impact rate to a setpoint value;
a vibration absorber including an oscillator movable along the working axis about a resting position and at least one spring driving the oscillator back into the resting position;
at least one sensor for ascertaining a first phase of a compression point of the hammer mechanism;
the at least one sensor for ascertaining a second phase of a turning point of the vibration absorber close to the tool; and
a damping controller adapting the setpoint value in such a way that a phase difference between the first phase and the second phase is less than a threshold value.

2. The hand-held power tool as recited in claim 1 further comprising an RPM-controlled motor driving the hammer mechanism.

3. A control method for a hand-held power tool as recited in claim 1 , comprising the following steps:
ascertaining the first phase of the compression point of the hammer mechanism;
ascertaining the second phase of a turning point of the vibration absorber close to the tool; and
adapting the setpoint value of the impact rate in such a way that the phase difference between the first phase and the second phase is less than the threshold value.

4. The control method as recited in claim 3 wherein the setpoint value is increased when the first phase lags behind the second phase, and the setpoint value is reduced when the first phase is ahead of the second phase.

Assignees

• Hilti Ag

Inventors

• Ontl Rainer
• Kohlschmied Frank
• Dieing Christoph

Classifications

• B25D17/24 Primary

  Damping the reaction force {(resiliently mounted handles B25D17/043; dampers in connections of hammers to backhoes E02F3/966)} · CPC title

• F16F7/1005

  characterised by active control of the mass · CPC title

• B25D2250/201

  for speed, e.g. drilling or percussion speed · CPC title

• B25D2250/005

  Adjustable tool components; Adjustable parameters · CPC title

• B25D2217/0092

  being spring-mounted · CPC title