IP Library › Granted Patent US 10,493,611
Granted Patent B2
US 10,493,611 · App. 15/532,597 · Granted Dec 3, 2019

Control method for a hand-held power tool

Inventors: Rainer Ontl (Landsberg am Lech, DE); Damir Cehajic (Durach, DE); Christoph Dieing (Isny, DE)
Assignee: Hilti Aktiengesellschaft
B25D17/24F16F7/104B25D2211/068B25D2216/0038B25D2217/0092B25D2250/005B25D2250/175B25D2250/201B25D2250/221
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Quick Facts
Patent No.
US 10,493,611
App. No.
15/532,597
Granted
Dec 3, 2019
Kind
B2
Abstract

The hand-held power tool has a tool holder ( 2 ) for holding a tool ( 4 ) along a working axis ( 12 ). A hammer mechanism ( 6 ) has a striker ( 15 ) that is moved periodically along the working axis at an impact rate. A drive control ( 18 ) of the hammer mechanism ( 6 ) sets the impact rate to a set point value. A vibration absorber ( 19 ) has an oscillator ( 21 ) that moves along the working axis ( 12 ) about a resting position and one or multiple springs ( 20 ) that drive the oscillator ( 21 ) back into the resting position. A calibration phase comprises the following steps: detection of an acceleration using the acceleration sensor ( 24 ); determination of a minimum of the acceleration by varying the impact rate in a range of between 90% and 110% of the set point value; and adjusting the set point to the impact rate associated with the ascertained minimum.

Claims (11)

1. A control method for a hand-held power tool including a machine housing, a handle fastened to the machine housing for guiding the hand-held power tool during operation, a tool holder for holding a tool on a working axis, a hammer mechanism including a striker moving periodically at an impact rate on the working axis, a drive control of the hammer mechanism setting the impact rate to a setpoint value, a vibration absorber including an oscillator moving with respect to the working axis back and forth from a resting position and at least one spring driving the oscillator back into the resting position, an acceleration sensor attached to a machine housing for detecting accelerations along the working axis, the control method comprising a calibration phase having the following steps:

detecting an acceleration with the aid of the acceleration sensor;

ascertaining a minimum of the acceleration by varying the impact rate in a range between 90% and 110% of the setpoint value;

adjusting the setpoint value to the impact rate associated with the ascertained minimum; and

driving the hammer mechanism at the impact rate adjusted to the setpoint value.

2. The control method as recited in claim 1 wherein the at least one spring includes a first spring on one side of the oscillator and a second spring on another side of the oscillator.

3. The control method as recited in claim 1 wherein the oscillator moves back and forth guided in a linear bearing along a linear bearing axis parallel or inclined less than 30 degrees in relation to the working axis.

4. The control method as recited in claim 1 further comprising storing a most recently determined setpoint value of the setpoint value of the impact rate in a data memory.

5. The control method as recited in claim 1 further comprising accelerating the motor to the setpoint value using an actuating system switch.

6. The control method as recited in claim 1 further comprising stepwise reducing a rotational speed of the power tool in relation to a setpoint rotational speed during the calibration phase.

7. The control method as recited in claim 1 further comprising continuously reducing a rotational speed of the power tool in relation to a setpoint rotational speed during the calibration phase.

Assignments (1)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Aug 23, 2017
From: ONTL, RAINER; CEHAJIC, DAMIR; DIEING, CHRISTOPH
To: HILTI AKTIENGESELLSCHAFT
Reel/Frame 043374/0253 →
Priority Claims (1)
EP 14196019 · Dec 3, 2014 · regional
Continuity (1)
Related Publication 20170361447A1 · Dec 21, 2017