# US 10,369,686 B2 · Hand-held power tool and control method therefor

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- Number: US 10,369,686 B2
- Document ID: US10369686B2
- Status: Granted
- Kind: B2
- Application number: 15/532,632
- Filed: 2015-12-01
- Published: 2018-01-04
- Granted: 2019-08-06
- Earliest claimed: 2014-12-03
- Assignees: Hilti Aktiengesellschaft
- Applicants: Hilti Aktiengesellschaft
- Inventors: Rainer Ontl; Frank Kohlschmied; Christoph Dieing
- Web page: https://patentgrep.com/patent/US10369686B2

## CPC

- B25D 17/24: Damping the reaction force {(resiliently mounted handles B25D17/043; dampers in connections of hammers to backhoes E02F3/966)}
- B25D 11/125: {with a fluid cushion between the crank drive and the striking body}
- B25D 16/00: Portable percussive machines with superimposed rotation {, the rotational movement of the output shaft of a motor being modified to generate axial impacts on the tool bit (combined percussion and rotary drilling adapted for earth drilling E21B6/00)}
- F16F 7/104: the inertia member being resiliently mounted {(F16F7/1022 takes precedence)}
- B25D 2211/068: Crank-actuated impulse-driving mechanisms
- B25D 2217/0092: being spring-mounted
- B25D 2250/005: Adjustable tool components; Adjustable parameters
- B25D 2250/175: Phase shift of tool components
- B25D 2250/201: for speed, e.g. drilling or percussion speed
- B25D 2250/221: Sensors
- F16F 7/1005: {characterised by active control of the mass}
- B25D: PERCUSSIVE TOOLS {(percussive machines for forging B21J; hand-held drilling machines, in general B23B45/00, for wood B27C3/08; drilling machines, used for mining or quarrying, with reciprocating tool which is turned intermittently when out of contact with the working face E21B1/00)}
- F16F: SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION

## 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.

## Claims

### Claim 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.

### Claim 2 (depends on 1)

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

### Claim 3 (depends on 1)

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.

### Claim 4 (depends on 3)

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.