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Bosch Rexroth AG
| Tightening Technology
3 608 870 A47
Nexo cordless Wi-Fi nutrunner
| 3 608 870 A47/2019-10
Torque threshold
The torque threshold is a parameter to help measure the angle of turn for a target or monitoring
function. The monitoring function of the angle is started as soon as the measured torque for the bolt
reaches the value for the torque threshold for the first time. Afterwards, the torque threshold has no
more influence on the tightening process, except for angle correction.
Chord angle
The chord angle is an additional parameter for determining the gradient.
Controller
Where the Nexo cordless Wi-Fi nutrunner is concerned, the controller is the tightening controller
integrated in the nutrunner.
Monitoring function
The monitoring function keeps track that the upper and lower limits are complied with during the
tightening process by checking a monitoring parameter (e.g. gradient).
If the monitoring function has switching capabilities, the tightening step will be terminated
immediately if a limit is exceeded. If it is has no switching capabilities, the step result changes to
NOK, even if the target parameter has been reached.
Monitoring parameter
The monitoring parameter is the measured quality (e.g. gradient) of a tightening step that must be
kept within specific limits in order for a tightening process to be performed safely. If the limits are
violated, the tightening step may be terminated.
Angle correction
The angle correction is an additional parameter to measure the angle of turn. Since the angle of turn
is never measured directly on a bolt, but above the output drive, there is a small deviation between
the measured angle and the angle on the bolt as a result of the torsion of the output drive due to the
torque. This deviation can be avoided with an angle correction at the end of the tightening process
(never during tightening!). The angle value measured at the end of tightening after falling below the
torque threshold is then used as the target or last monitoring parameter (the torsion of the output
drive has then reset itself).
Target function
The target function controls the process sequence of the tightening step by monitoring the target
parameter (e.g. torque) and ends the step if the parameter value has reached its target value.
Target parameter
The target parameter is the measured variable (e.g. torque) of a tightening step, which must reach
a specific value (target value) for a tightening process to be performed successfully. The tightening
step is terminated once the target value has been reached.
Additional function
The additional function defines further parameters for the tightening step. Although they have an
effect on the tightening process (e.g. start-up suppression, speed setting), additional functions
cannot interrupt it. They do not carry out an OK/NOK evaluation.
Additional parameters
Additional parameters are the parameter values in a tightening step, which influence the tightening
process (e.g. target speed, torque threshold), but which cannot interrupt the tightening process.
