Invention Grant
- Patent Title: Power screwdriver
- Patent Title (中): 电动螺丝刀
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Application No.: US12451014Application Date: 2008-04-21
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Publication No.: US08171827B2Publication Date: 2012-05-08
- Inventor: Marc Gareis
- Applicant: Marc Gareis
- Applicant Address: DE Vaihingen/Enz
- Assignee: LOESOMAT Schraubtechnik Neef GmbH
- Current Assignee: LOESOMAT Schraubtechnik Neef GmbH
- Current Assignee Address: DE Vaihingen/Enz
- Agency: Collard & Roe, P.C.
- Priority: DE102007019408 20070423
- International Application: PCT/DE2008/000677 WO 20080421
- International Announcement: WO2008/128525 WO 20081030
- Main IPC: B25B23/147
- IPC: B25B23/147

Abstract:
The invention relates to a power screwdriver (10) comprising a motor (12) and a control circuit (22) which switches the motor (12) off by means of a switch-off signal (s_Stop) when it reaches a preset desired torque value (Md_Soll), and a supporting arm (18) which absorbs energy during screwing. The invention is characterized by a voltage limiting circuit (46) that limits the motor voltage (u_Mot) occurring on the motor (12) when the energy stored in the supporting arm (18) of the motor (12), which is driven as the generator and rotates counter to the direction of drive, is dissipated, to a predetermined limiting voltage (u_Lim). The limiting voltage (u_Lim) is fixed in such a manner that the motor (12) is capable of rotating without counter-torque counter to the direction of drive when operated in the generator mode and that yet no inadmissible overvoltages occur.
Public/Granted literature
- US20100101381A1 POWER SCREWDRIVER Public/Granted day:2010-04-29
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