US 11,529,718 B2Granted

Method and device for tightening screw joints

AssigneeLiebherr-Components Biberach GmbH

InventorsJan Parlow, Ilaka Mupende, Peter Barton

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Abstract

A method and apparatus for tightening a screw connection having a motor-operated screwdriver unit, wherein the angle of rotation and the torque are determined during the tightening to be able to stop the tightening process on reaching a desired tightening tension. An increase in the torque over the angle of rotation is determined by a determination device in a first tightening region and a change in the increase in the torque over the angle of rotation is determined in a second, following tightening region, with the screwdriver unit being stopped by a control device on reaching or exceeding of a maximum permitted change in the increase and/or of a change speed that is determined with reference to the increase that occurred in the first tightening region.

Claims17

Dependent claims

An apparatus for tightening a screw connection comprising:

a motor-driven screwdriver unit;
determination means for determining the torque (M) and the angle of rotation (φ) during the tightening of the screw connection;
a determination device:
for determining in a first tightening region, one or both of:
an increase of the torque (M) over the angle of rotation (φ);
and
a change of the torque (M) increase over the angle of rotation (φ);
and
for determining:
if the increase of the torque over the angle of rotation is determined, a change of the increase in the torque over the angle of rotation;
and
if the chance of the torque increase over the angle of rotation is determined, a change speed of the increase of the torque over the angle of rotation;
an evaluation unit for fixing:
if the change of the increase in the torque over the angle of rotation is determined, a maximum permitted change of the increase of the torque;
and
if the change speed of the increase of the torque over the angle of rotation is determined, a maximum permitted change speed of the increase of the torque;
and
a control device to, if the maximum permitted chance speed of the increase of the torque is fixed, stop the screwdriver unit on reaching and/or exceeding the maximum permitted change speed of the increase of the torque;
wherein the first tightening region is fixed with reference to one or more of:
a torque amount;
if determined, the increase of the torque over the angle of rotation;
and
if determined, the change of the torque increase over the angle of rotation;
as an elastic tightening region in which the screw connection is elastically deformed.

21 more elements

An apparatus for tightening a screw connection comprising:

a motor-driven screwdriver unit;
determination means for determining the torque (M) and the angle of rotation (cp) during the tightening of the screw connection;
a determination device:
for determining in a first tightening region, one or both of:
an at least approximately constant rate of increase of the torque (M) over the angle of rotation (φ);
and
a change of the at least approximately constant rate of torque (M) increase over the angle of rotation (w);
and
for determining:
if the at least approximately constant rate of increase of the torque over the angle of rotation is determined, a change of the at least approximately constant rate of increase in the torque over the angle of rotation:
and
if the at least approximately constant rate of change of the torque increase over the angle of rotation is determined, a change speed of the at least approximately constant rate of increase of the torque over the angle of rotation;
an evaluation unit for fixing:
if the change of the at least approximately constant rate of increase in the torque over the angle of rotation is determined, a maximum permitted change of the increase of the torque;
and
if the change speed of the at least approximately constant rate of increase of the torque over the angle of rotation is determined, a maximum permitted change speed of the increase of the torque;
and
a control device to, if the maximum permitted change speed of the increase of the torque is fixed, stop the screwdriver unit on reaching and/or exceeding the maximum permitted change speed of the increase of the torque;
wherein the first tightening region is fixed with reference to one or more of:
a torque amount;
if determined, the at least approximately constant rate of increase of the torque over the angle of rotation;
and
if determined, the at least approximately constant rate of change of the torque increase over the angle of rotation;
as an elastic tightening region in which the screw connection is elastically deformed.

21 more elements

A method of tightening a screw connection with a motor-driven screwdriver unit in which an angle of rotation and torque are determined during the tightening comprising:

determining in a first tightening region a first change;
determining in a second, following tightening region a second change;
and
stopping the screwdriver unit on reaching or exceeding a maximum permitted change;
wherein:
the maximum permitted change is based on the determined first change and the determined second change;
the first change is selected from the group consisting of:
an at least approximately constant rate of increase of the torque over the angle of rotation;
a change of the at least approximately constant rate of torque increase over the angle of rotation;
and
a combination thereof;
the second change is a change speed of the at least approximately constant rate of increase of the torque over the angle of rotation;
the maximum permitted change is selected from the group consisting of:
a maximum permitted change of the at least approximately constant rate of increase of the torque;
a maximum permitted change speed of the at least approximately constant rate of increase of the torque;
and
a combination thereof;
the first tightening region is fixed with reference to one or more of a torque amount, the at least approximately constant rate of increase of the torque over the angle of rotation, and the change of the at least approximately constant torque increase over the angle of rotation, as an elastic tightening region in which the screw connection is elastically deformed;
and
one or both of the maximum permitted change of the at least approximately constant rate of increase of the torque and the maximum permitted change speed of the at least approximately constant rate of increase of the torque is fixed such that the screw connection is preloaded to a yield point.

17 more elements

Dependencies are inferred from the claim text.

Facts

Application: 16/493,669Filed 13 Mar 2018
Priority: DE 10 2017 002 440.513 Mar 2017
Published: US 2020/0130152 A130 Apr 2020
Granted: 20 Dec 2022
Term ends: Not estimatedThe source records don’t support an estimate.

Classification7 codes

B25B 23/14
Details of, or accessories for, spanners, wrenches, screwdrivers: arrangement of torque limiters or torque indicators in wrenches or screwdrivers
B25B 21/00
Portable power-driven screw or nut setting or loosening tools
B23P 19/066
Arrangements for torque limiters or torque indicators in screw or nut setting machines: by electrical means
B25B 23/145
Arrangement of torque limiters or torque indicators in wrenches or screwdrivers: specially adapted for fluid operated wrenches or screwdrivers