Power-impact or pulse screwing method
AssigneeRobert Bosch GmbH
InventorsAugust Layer, Hans Rudolf, Bernd Grammer, Heinz Veitinger
Life of this patent
Estimating the term…
Abstract
A method for tightening a screw utilizes a power-impact or pulse driver. The prestressing force in the screw to be tightened is increased step-by-step during the tightening operation and evaluated. By detecting the prestressing force in the screw on a step-by-step basis, the step heights pertaining to the increase in the prestressing force and the change in the step heights are used as criteria for the screw-coupling quality and for controlling the screw-coupling operation. In the same way, the number of impacts or pulses is also used as a criterion for the screw-coupling quality and for controlling the screw-coupling operation.
Claims9
A method for tightening a screw, comprising the steps of:
- applying individual torque pulses to the screw via one of a power impact driver and a pulse driver, thereby tightening the screw in a step-by-step manner;
- detecting, via an ultrasound echo-time measurement, at least one screwing parameter as a physical quantity indicating deformation of the screw;
- and
- switching-off the one of the power impact driver and the pulse driver as a function of the detected at least one screwing parameter when the at least one screwing parameter indicates a change in the physical response of the screw.
A screwing device for tightening a screw, comprising:
- one of a power-impact and a pulse driver for applying a number of individual torque pulses to the screw, thereby tightening the screw in a step-by-step manner;
- an ultrasound echo-time measurement sensor, connected to one of the Dower-impact driver and the pulse driver, for measuring a pre-stressing force on the screw;
- and
- a control unit connected to one of the power-impact driver and the pulse driver, the control unit including
- a computing device for determining a switch-off value for switching-off the one of the power-impact driver and the pulse driver when the pre-stressing force indicates a change in physical response of the screw, and
- an input device for receiving the switch-off value and at least one data output.
Dependencies are inferred from the claim text.