Patent References 2720803 3827750 Multi-stage tightening system Method for tightening bolts Microprocessor control yield point tightening system Apparatus and method for determining torque, presenting digital torque readout and automatic cycling and termination of wrench operation in a torque wrench system Tightening system and a method of tightening Torque control for automatic connector assembly tool Patent #: 4858312 InventorsAssigneeApplicationNo. 459332 filed on 12/29/1989US Classes:173/181, Having torque sensor173/1PROCESSESExaminersPrimary: Eley, Timothy V.Assistant: Fridie, Willmon Jr. Foreign Patent References
International ClassB23Q 005/00AbstractThe output shaft of a nut runner for tightening a fastener such as a bolt is first rotated with a first torque at a first speed. When the tightening torque of the output shaft reaches a preset switching torque, the first torque first speed rotation of the output shaft is interrupted, and thereafter the output shaft is rotated with a second torque at a second speed. When the tightening torque then reaches a preset snug torque, the second torque second speed rotation of the output shaft is interrupted, and thereafter the output shaft is rotated with a third torque at a third speed. When the tightening torque reaches a preset final torque, the third torque third speed rotation of the output shaft is stopped, thus completing the tightening of the fastener. | |