EP 0419435 A3 19911204 - METHOD AND DEVICE FOR TIGHTENING THREADED JOINTS
Title (en)
METHOD AND DEVICE FOR TIGHTENING THREADED JOINTS
Publication
Application
Priority
SE 8903134 A 19890922
Abstract (en)
[origin: EP0419435A2] The invention concerns a method and a device for tightening threaded joints in two subsequent steps, namely a first step during which a joint is tightened to a predetermined torque snug level and a second step during which the joint is further tightened up to a final predetermined pretension level. During the second tightening step the torque delivered by the power tool (10) comprised in the device is gradually increased at a rate exceeding the highest torque rate expected from the joint to be tightened. The power tool (10) comprises an electric brushless AC-motor which is supplied with power from a variable frequency output inverter (11), and the gradual increase in output torque from the power tool (10) is accomplished by the phase lag in the AC-motor as a result of a gradually increased output frequency from the power supply means (11).
IPC 1-7
IPC 8 full level
B25B 23/14 (2006.01); B25B 23/147 (2006.01); B25B 23/151 (2006.01)
CPC (source: EP)
B25B 23/14 (2013.01); B25B 23/147 (2013.01)
Citation (search report)
- [X] EP 0221528 A2 19870513 - SPS TECHNOLOGIES [US]
- [X] DE 3330028 A1 19840419 - DAIICHI DENTSU KK [JP]
Designated contracting state (EPC)
DE FR GB IT
DOCDB simple family (publication)
EP 0419435 A2 19910327; EP 0419435 A3 19911204; EP 0419435 B1 19950719; DE 69020994 D1 19950824; DE 69020994 T2 19960411; JP 3505175 B2 20040308; JP H03184775 A 19910812; SE 8903134 D0 19890922; SE 8903134 L 19910323
DOCDB simple family (application)
EP 90850316 A 19900924; DE 69020994 T 19900924; JP 25204690 A 19900925; SE 8903134 A 19890922