Gm Global Technolgoy Operations, Inc.

David H Shea

Mike M Ghiran

Spyros Pete Mellas

Brian K Bartnick

Paul D Larsen

Thomas W McClure

Darrell W Rebman

Daniel K Owusu

A method of separating a length of single-strand wire at a notch location includes forming at least one notch in the length of single-strand wire at the notch location. The notch location is subjected to tensile strain until the notch location ruptures at the notch to separate the length of single-strand wire into a first single-strand wire and a second single-strand wire. After separation of the length of single-strand wire, the first and second single-strands each present a generally tapered end that corresponds to the notch location.

Method of separating a length of single-strand wire

A spark plug orientation method may include forming a spark plug housing by advancing a tool a first distance in a first axial direction into a spark plug bore to create a spark plug seat using a seat forming portion of the tool. The tool may be displaced a second distance in a second axial direction generally opposite the first axial direction to provide a predetermined axial orientation between the thread forming portion of the tool and the spark plug seat. The spark plug bore may be engaged at a first predetermined rotational position and the tool may be displaced in an orbital motion and in the second axial direction at a predetermined rate to form a threading on the spark plug bore providing a starting point of the threading at a second predetermined rotational position proximate the spark plug seat.

Method for providing a controlled spark plug orientation in an engine structure

A tool adapted to form and method of forming a tapped hole within a workpiece in a single pass, includes a piercing section operable to punch a pilot hole in and produce a slug attached to the workpiece, and a tapping section operable to form a female thread along the periphery of the hole, and more preferably, an extruding section operable to push workpiece material away from the exterior surface defined thereby, an expanding section operable to expand the diameter of the hole, a sealing section operable to seal the hole during a hydroforming process, and a burnishing section operable to further expand and treat the periphery of the hole prior to tapping.

Tool for and method of forming at tapped hole in a single pass

The thread form can provide a controlled thread stiffness which can more evenly distribute loads and can be less sensitive to changes in relative pitch. The controlled stiffness of the thread can provide a desired cantilever bending of the thread under assembled load. The thread form can utilize a traditional thread form at and/or above the pitch diameter, thereby maintaining the area of contact close to that of a standard thread form. Standard gaging implements can be used to ascertain the thread pitch and for quality control. The thread form includes a side extending between the crest and the root. The side has a first portion extending from the crest toward the root and the second portion extending from the first portion toward the root. The first and second portions extend toward the root in different orientations relative to the thread.

Thread profile modification for controlled stiffness

A tool forms a threaded hole in a hydroformed part while the part remains in a hydroforming die cavity and under pressure. The tool has a hole-piercing end portion adapted on advancement of the tool to pierce and form a hole in the part and an extruding portion adapted on continued tool advancement to extrude an annular extrusion that extends into the tube interior. An adjacent sealing portion of the tool seals the hole during the ongoing advancement and extrusion of the annular extrusion so that hydroforming fluid remains under pressure. A thread-forming portion of the tool forms an internal thread within the annular extrusion upon the continued advancement and rotation of the tool.

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Lake Orion, MI, United States of America

David H Shea