InventorUS Classes173/1, PROCESSES173/181, Having torque sensor81/469, Means for regulating motor318/430MOTOR LOAD, ARMATURE CURRENT OR FORCE CONTROL DURING STARTING AND/OR STOPPINGAttorney, Agent or FirmForeign Documents
International ClassesB25B 21/00B25B 23/147 H02P 7/28 Issued Patent Number:8025106Abstract textDisclosed is a method for screwing in and tightening a screw connection (1) to a predetermined tightened level (2), especially a predetermined torque level (2) or a predetermined pretension level, with the aid of a hand-held screwing tool (3) comprising a regulated drive unit (4) and/or control functionality, particularly an electric nut runner (3). A tightening phase (B-C-D), during which the screw head rests against the supporting surface (6) of the screw connection (1), starts following a screwing phase (A). In order to improve said method, the speed (N) of the screwing tool (3) is increased to an output speed (7) for the tightening phase (B-C-D) within an acceleration time (8) in the tightening phase (B-C-D) and is lowered within a delay time (9) prior to or until reaching the predetermined tightened level (2). The combined acceleration time (8) and delay time (9) represents the predominant part of the entire tightening phase (B-C-D), especially in relation to the traveled angle of twist (W) of the screw connection (1), the acceleration time (8) being shorter than the delay time (9). |
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