Textron Corporation

John S Milliser

James T McGuire

Michael D Marvell

An improved method and joint structure are provided for assembling a self-clinching fastener to sheet material, particularly thin sheet metal, in which an aperture and a peripheral flange are formed in the sheet metal; thereafter the shank portion of the fastener is inserted into the flange followed by clinching the fastener to the flange to secure the assembly. The sheet metal aperture and peripheral flange can be fabricated in a single work station in which the fabricating tooling punches the sheet metal aperture and extrudes or shapes the peripheral flange between a pair of forming dies. Assembly of the fastener joint with the flanged metal is performed in a second work station in which the fastener shank is inserted into the flange and then the head portion of the fastener is driven into the flange material to begin the clinching step. In the clinching operation the fastener head bends the flange material radially outwardly into enagement with the contiguous sheet metal to produce effectively doubled sheet metal thickness at the annular periphery of the aperture. Further driving the head portion into the bent flange displaces and cold-deforms a portion of the flange material radially inwardly into a locking groove provided in the inserted fastener shank to produce mechanical interlock of the clinched assembly.

Method for assembling a self-clinching fastening structure

An improved joint structure and tooling apparatus are provided for assembling a self-clinching fastener to sheet material, particularly sheet metal. The fastener includes head and shank portions with an intermediate locking groove formed in the shank. The fastener shank projects through the aperture and the head is at least partially embedded within the peripheral material surrounding the sheet metal aperture. A portion of the peripheral sheet metal is disposed within the groove to form a mechanical interlock for securement of the joint assembly. The shank has an outwardly flared end portion which is staked so that it has an exposed surface coplanar or flush with the exposed, opposite surface of the sheet material relative to the embedded fastener head, which provides a smooth continuous undersurface of the joint. In a preferred embodiment, the flattened and staked end portion of the shank clamps the peripheral sheet material against the fastener head adjacent to the grooved mechanical interlock to further promote securement of the joint assembly for particular resistance to side loads or shear forces on the joint assembly in subsequent use. In another aspect of the invention, the tooling apparatus for securing the self-clinching of the fastener to the apertured sheet material comprises a die member for supporting the apertured sheet metal and includes a projecting cam portion for staking the fastener.

Clinch type fastener structure and tooling

An improved method and joint structure are provided for assembling a self-clinching fastener to sheet material, particularly thin sheet metal, in which an aperture and a peripheral flange are formed in the sheet metal; thereafter the shank portion of the fastener is inserted into the flange followed by clinching the fastener to the flange to secure the assembly. The sheet metal aperture and peripheral flange can be fabricated in a single work station in which the fabricating tooling punches the sheet metal aperture and extrudes or shapes the peripheral flange between a pair of forming dies. Assembly of the fastener joint with the flanged metal is performed in a second work station in which the fastener shank is inserted into the flange and then the head portion of the fastener is driven into the flange material to begin the clinching step. In the clinching operation the fastener head bends the flange material radially outwardly into engagement with the contiguous sheet metal to produce effectively doubled sheet metal thickness at the annular periphery of the aperture. Further driving the head portion into the bent flange displaces and cold-deforms a portion of the flange material radially inwardly into a locking groove provided in the inserted fastener shank to produce mechanical interlock of the clinched assembly.

Clinch type fastening structure

A self-clinching fastener of the type for connection to a workpiece comprising sheet material, includes a head and a shank, with a groove formed in the shank, with the head being embeddable in the sheet material to displace material thereof into the groove to form a mechanical interlock between the material of the sheet material and the fastener. The head includes a plurality of radially disposed projections extending axially outwardly of an undersurface thereof and intermediate the undersurface and the groove. These projections each include an axially facing recess therein, such that the material of the workpiece being displaced will flow into the groove and the recesses in the projections, to lock the fastener to the workpiece. The shank may also include an extruding portion to resize an aperture in the sheet material, prior to the deforming of said sheet material by said head.

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Rochester, IN, United States of America

John S Milliser