Method and apparatus for driving interference-fit fasteners
AssigneeGrumman Aerospace Corporation
InventorBasil P. Leftheris
Life of this patent
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Abstract
Method and apparatus for driving an interference-fit fastener by electromagnetically generating a stress wave, conditioning the stress wave, and passing the stress wave through the fastener, the stress wave is reflected from the remote free end of the fastener to impart a high velocity to the fastener relative to the surface of its receiving aperture to overcome the frictional forces existing there between and draw the interference fastener into the receiving aperture.
Claims11
A process for driving an interference-fit fastener into a receiving aperture having a slightly smaller diameter than the fastener, comprising the steps of:
- a. electromagnetically generating a stress wave having a high particle velocity;
- b. conditioning the high velocity stress wave to control the intensity and length of the high velocity stress wave to provide an output stress wave which maintain a high stress level, the stress level of the conditioned stress wave being less than the yield stress of the interference-fit fastener to prevent plastic deformation thereof, the length of the stress wave being greater than the length of the interference-fit fastener;
- and
- c. applying the conditioned high velocity stress wave to one end of thee interference-fit fastener causing a tensile elongation in the direction of propagation and contraction at right angles to the direction of propagation, the conditioned high velocity stress wave reflecting from the remote free end of the interference-fit fastener to impart a high velocity to the remote free end of the interference-fit fastener so that frictional forces are overcome and the interference-fit fastener is drawn into the receiving aperture.
A tool for driving an interference-fit fastener into a receiving aperture having a slightly smaller diameter than the fastener, comprising:
- a. means for electromagnetically generating a stress wave having a high particle velocity;
- b. conditioning means for controlling the intensity and length of the high velocity stress wave to provide an output stress wave which maintains a high stress level for a substantial portion of the length of the stress wave, the stress level of the stress wave resulting from the conditioning means being less than the yield stress of the interference-fit fastener to prevent plastic deformation thereof, the length of the stress wave being greater than the length of the interference-fit fastener;
- and
- said interference-fit fastener including a first end for engagement with said conditioning means and a remote end for engagement with the receiving aperture, the conditioned stress wave causing a tensile elongation in the direction of propagation and contraction at right angles to the direction of propagation and reflecting from the remote free end of the interference-fit fastener to impart a high velocity to the remote free end of said interference-fit fastener so that the frictional forces are overcome and the interference fastener is drawn into the receiving aperture.
Dependencies are inferred from the claim text.