Rotatable piercing tools for forming bossed holes
AssigneeTechnisch Handels- en Adviesbureau van Geffen B.V.
InventorJohannes A. van Geffen
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Abstract
A rotary piercing tool for forming, in a metal plate or the wall of a metal tube, by pressure and friction-generated heat a bossed hole, said tool comprising a tapered active end portion at one end, a shank for its attachment in a chuck of a machine tool at the other end and a coaxial cavity extending from the free end of said shank to a place at a given distance from the free end of said active end portion.
Claims5
A rapidly rotatable piercing tool for forming, substantially by frictional heat and pressure, a hole surrounded by a boss in a metal plate or the wall of a metal tube, said tool having a tapered first portion, a second portion adjoining said first portion coaxially and having a shape, which is adapted to the shape of the hole to be formed, a third portion adjoining the second portion coaxially and a shank adjoining the third portion coaxially and meant for the attachment of the piercing tool in a machine tool, the piercing tool having in addition a coaxial cavity which extends from the free end of the shank to a place at a given distance from the leading end of the first portion and has such a shape as to ensure that the wall surrounding said cavity has in all places at least a predetermined thickness.
Dependencies are inferred from the claim text.