US 12,497,987 B1Granted

Cartridge mechanism and method for monitoring a clamping force exerted on a structure by a fastener during installation

AssigneeThe Boeing Company

InventorsShawn M. Arnett, Jeremy W. Sibley

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Abstract

A cartridge mechanism for monitoring a clamping force of a temporary fastener includes an inner assembly, an outer assembly, and a displacement indicating system. The inner assembly has an inner cap and an inner spring. The outer assembly has an outer cap and an outer spring. The displacement indicating system indicates an amount of compressive displacement of the inner and outer springs that represents attainment of a preliminary clamping force exerted on the structure by the temporary fastener. The inner spring is uncalibrated and has a spring constant substantially equal to that of the outer spring, which is calibrated to one-half the preliminary clamping force at the amount of compressive displacement indicated by the displacement indicating system. The outer assembly is removable from the inner assembly to result in a final clamping force exerted by the temporary fastener on the structure of approximately one-half the preliminary clamping force.

Claims20

Dependent claims

An interim manufacturing assembly, comprising:

a structure containing a plurality of fastener holes;
a plurality of temporary fasteners installed in the fastener holes;
a plurality of inner assemblies upon which the plurality of temporary fasteners are respectively mounted, and each inner assembly is configured to be temporarily coupled to a reusable outer assembly of a cartridge mechanism during fastener installation;
wherein:
the inner assembly at each temporary fastener includes:
an inner cap on which the temporary fastener is mounted;
an inner spring located between the inner cap and the structure;
the outer assembly includes:
an outer cap removably couplable to the inner cap of each inner assembly;
an outer spring located between the outer cap and the structure when the outer assembly is coupled to one of the inner assemblies;
a displacement indicating system configured to indicate an amount of compressive displacement of the inner spring and outer spring that represents attainment of a desired preliminary clamping force exerted on the structure at each fastener hole due to tightening of the temporary fastener;
the inner spring of each inner assembly is uncalibrated and has a spring constant substantially equal to that of the outer spring, which is calibrated to one-half the preliminary clamping force at the amount of compressive displacement indicated by the displacement indicating system;
and
the outer assembly of the cartridge mechanism is removable from each inner assembly and is reusable on other inner assemblies in a manner resulting in a final clamping force at each temporary fastener of approximately one-half the preliminary clamping force.

11 more elements

A cartridge mechanism for monitoring a clamping force exerted on a structure during installation of a temporary fastener, comprising:

an inner assembly, comprising:
an inner cap configured to receive a temporary fastener having a protruding pin assembly configured to be inserted into a fastener hole in a structure;
an inner spring positionable between the inner cap and the structure;
an outer assembly, comprising:
an outer cap removably couplable to the inner cap;
an outer spring positionable between the outer cap and the structure and encircling the inner spring;
a displacement indicating system integrated into the outer assembly and configured to indicate an amount of compressive displacement of the inner spring and outer spring that represents attainment of a desired preliminary clamping force exerted on the structure due to tightening of the temporary fastener;
wherein the inner spring is uncalibrated and has a spring constant substantially equal to that of the outer spring, which is calibrated to one-half the preliminary clamping force at the amount of compressive displacement indicated by the displacement indicating system;
and
the outer assembly is removable from the inner assembly to result in a final clamping force exerted by the temporary fastener on the structure of approximately one-half the preliminary clamping force.

7 more elements

A method of monitoring a clamping force exerted on a structure during installation of a temporary fastener, comprising:

providing a cartridge mechanism, comprising:
an inner assembly having an inner cap and an inner spring positionable between the inner cap and the structure;
an outer assembly having an outer cap removably coupled to the inner cap, and having an outer spring positionable between the outer cap and the structure and encircling the inner spring;
a displacement indicating system integrated into the outer assembly;
wherein the inner spring is uncalibrated and has a spring constant substantially equal to that of the outer spring, which is calibrated to one-half of a desired preliminary clamping force exerted on the structure at a compressive displacement indicated by the displacement indicating system;
mounting a temporary fastener on the inner cap to form a fastener-cartridge assembly;
positioning the fastener-cartridge assembly against the structure in a manner such that a pin assembly protruding from the temporary fastener extends into a fastener hole in the structure;
tightening the temporary fastener until the displacement indicating system indicates that the inner spring and outer spring haven been compressed by an amount representing attainment of a predetermined preliminary clamping force on the structure;
and
removing the outer assembly from the inner assembly to result in fastener-inner assembly providing a final clamping force exerted on the structure by the temporary fastener of approximately one-half the preliminary clamping force.

7 more elements

Dependencies are inferred from the claim text.