Method and device for operating a hand-held machine tool with a tangential impact mechanism

• US 10,065,297 B2
• Filed: 10/07/2013
• Issued: 09/04/2018
• Est. Priority Date: 10/08/2012
• Status: Active Grant

• Current Assignee: Hilti Aktiengesellschaft (Hilti Martin Family Trust)
• Original Assignee: Hilti Aktiengesellschaft (Hilti Martin Family Trust)
• Inventors: Worz, Joachim, Brandner, Michael
• Primary Examiner(s): Lopez, Michelle
• Application Number:
  US14/433,724
• Publication Number:
  US 20150246435A1
• Time in Patent Office: 1,793 Days
• Field of Search: 173 1, 173176, 173178
• CPC Class Codes: B23B 2270/48 Measuring or detecting
• CPC Class Codes: B25B 21/02 with means for imparting impact to screwdriver blade or nut socket
• CPC Class Codes: B25B 23/1475 for impact wrenches or screwdrivers

Abstract

The invention relates to a method for operating a hand-held machine tool with a tangential impact mechanism which can be driven by means of a drive shaft and an electric motor, according to which method an actual torque provided by the drive shaft is adjusted to a required torque depending on a measured motor current, wherein the required torque is less than a triggering torque of the tangential impact mechanism.

Claims

1. A method for operating a hand-held machine tool with an impact mechanism driven by a drive shaft and an electric motor, the method comprising adjusting an actual torque provided by the drive shaft to a required torque, wherein the required torque is determined by measuring current of the electric motor, the method including switching the impact mechanism on when a value of the determined electric motor current exceeds a stipulated electric motor current threshold value.

2. The method according to claim 1, comprising regulating the actual torque to the required torque.

3. The method according to claim 1, including determining the required torque as a function of the measured electric motor current, wherein the actual torque is regulated to the determined required torque.

4. The method according to claim 1, wherein the stipulated electric motor current threshold value is at least 15 amperes.

5. The method according to claim 1, comprising adjusting the actual torque to the required torque by manually activating a switch to switch the actual torque off.

6. The method according to claim 1, comprising changing the electric motor current to a value less than the stipulated electric motor current threshold value.

7. The method according to claim 1, comprising adjusting the actual torque to the required torque by controlling the electric motor with an adjustment signal.

8. The method according to claim 7, comprising forming the adjustment signal as a pulse width modulated signal.

9. The method according to claim 1, wherein the electric motor is a brush motor.

10. The method according to claim 1, wherein the electric motor is a brush-less motor.