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US 6,742,235 B2Granted
Fastening of sheet material
AssigneeHenrob Limited
InventorsStuart Edmund Blacket, Nicholas Richard Clew
Life of this patent
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AssigneeHenrob Limited
InventorsStuart Edmund Blacket, Nicholas Richard Clew
Estimating the term…
A fastener such as a self piercing rivet is inserted into sheet material without full penetration such that the deformed end of the rivet remains encapsulated by an upset annulus of the sheet material. The sheet material is disposed between a nose and a die of fastening apparatus. The rivet is inserted into the sheet material by means of a plunger that is reciprocal relative to the nose. Prior to rivet insertion no significant clamping force is applied to the sheet material and material immediately around the rivet insertion location is allowed to flow towards the rivet as to rivet is inserted. Thereafter during a second stage (being after said first stage) of rivet insertion a clamping force of sufficient magnitude is applied between the nose and the die in the region around the rivet insertion location so as substantially to prevent flow of displaced sheet material away from the rivet. The invention may also be applied to panel clinching. The resulting joints are of improved mechanical strength and fatigue life. Certain components of the apparatus of the present invention have an improved life expectancy.
A method for inserting a fastener into sheet material comprising inserting the fastener into at least one sheet without full penetration such that a deformed end of the fastener remains encapsulated by an upset annulus of the sheet material, the sheet material being disposed between a nose and a die of the fastening apparatus and the fastener being inserted into the sheet material by means of a plunger that is reciprocal relative to the nose, characterized in that, during a first stage of fastener insertion there is no significant clamping force so that the sheet material around the fastener insertion location is free to be displaced without significant constraint towards the fastener by virtue of its insertion, and thereafter during a second stage (being after said first stage) of fastener insertion a clamping force of sufficient magnitude is applied between the nose and the die in the region around fastener insertion location so as substantially to prevent flow of displaced sheet material away from the fastener.
A method for inserting a fastener into sheet material comprising inserting the fastener into at least one sheet without full penetration such that a deformed end of the fastener remains encapsulated by an upset annulus of the sheet material, the sheet material being disposed between a nose and a die of the fastening apparatus and the fastener being inserted into the sheet material by means of a plunger that is reciprocal relative to the nose, characterized in that, during a first stage of fastener insertion comprising entry of the fastener into the sheet material, no clamping force is applied to the sheet material in the region around the fastener insertion location and the sheet material around the fastener insertion location is displaced towards the fastener by virtue of its insertion, and thereafter during a second stage (being after said first stage) of fastener insertion comprising the fastener being pressed substantially flush with an upper surface of the sheet material, a clamping force of sufficient magnitude is applied between the nose and the die in the region around fastener insertion location so as substantially to prevent flow of displaced sheet material away from the fastener.
A method for inserting a fastener into sheet material comprising inserting the fastener into at least one sheet without full penetration such that a deformed end of the fastener remains encapsulated by an upset annulus of the sheet material, the sheet material being disposed between a nose and a die of the fastening apparatus and the fastener being inserted into the sheet material by means of a plunger that is reciprocal relative to the nose, characterized in that, during a first stage of fastener insertion the sheet material around the fastener insertion location is displaced towards the fastener by virtue of its insertion, and thereafter during a second stage (being after said first stage) of fastener insertion a clamping force of sufficient magnitude is applied between the nose and the die in the region around fastener insertion location so as substantially to prevent flow of displaced sheet material away from the fastener, said clamping force is provided by compression of a compressible member that is disposed between the plunger and the nose.
An apparatus for inserting a fastener into sheet material without full penetration such that a deformed end of the fastener remains encapsulated by an upset annulus of the sheet material, said apparatus comprising a nose in which is disposed a reciprocal plunger, means for feeding fasteners successively to the nose for insertion by the plunger into the sheet material, a die aligned with the plunger for deforming the fastener being inserted, the sheet material being disposed between the nose and die during the fastening operation, characterized in that there is provided means for applying a clamping force at a predetermined point during insertion of the fastener, said means for applying the clamping force comprising a compressible member that is disposed between the plunger and the nose and is compressed when the plunger reaches a predetermined position relative to the nose and said means for applying the clamping force allowing the sheet material around the fastener insertion location to be displaced by the fastener towards the fastener during a first stage of fastener insertion, and thereafter during a second stage (being after said first stage) of fastener insertion applies a clamping force of sufficient magnitude between the nose and the die in the region around fastener insertion location so as substantially to prevent flow of displaced sheet material away from the fastener.
A panel clinching method wherein two or more sheets of material are deformed into locking engagement, the sheet material being disposed between a nose and a die of a fastening apparatus, the sheet material being deformed by means of a plunger that is reciprocal relative to the nose, characterized in that, during a first stage of deformation, there is no significant clamping force so that the sheet material around the deformation region is free to be displaced without significant constraint towards the plunger by virtue of its insertion into the material, and thereafter during a second stage (being after said first stage) of deformation a clamping force of sufficient magnitude is applied between the nose and the die in the region around the deformation so as substantially to prevent flow of displaced sheet material away from the plunger.
Dependencies are inferred from the claim text.