Punch Pin Geometry for Deeper TORX Socket Flutes

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Solution Overview

Problem

Smaller TORX PLUS® and TORX® brand recess fasteners with applied coatings, such as zinc-flake coatings, experience non-uniform coating thickness, leading to issues with drive tool fitment due to thicker coatings on flutes, causing them to become less deep and preventing proper insertion.

Innovation Solution

A punch pin with modified dimensions, specifically increasing the A' REF dimension by 0.05 mm and adjusting the F' a-REF and F' b-REF distances, forms deeper flutes and less oblong lobes, allowing for uniform coating deposition without compromising drive tool compatibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a coating is applied to smaller TORX PLUS and TORX brand recess fasteners, then corrosion protection and surface properties are improved, but the coating thickness becomes non-uniform with thicker coatings on flutes, causing drive tool fitment issues

Engineering Contradiction:

Improvecorrosion protectionVSAvoidcoating thickness uniformity

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The punch pin is designed with non-uniform dimensions where the lobes have different radii of curvature (first radius vs second radius) and the flutes have varying depths. This creates local variations in the socket geometry that compensate for the non-uniform coating deposition, ensuring that the coated surface maintains consistent functional dimensions for drive tool engagement.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The invention modifies the geometric parameters of the punch pin, specifically increasing the A dimension and adjusting the lobe and flute dimensions, to account for the expected coating thickness. This parameter adjustment ensures that after coating, the socket retains the proper TORX or TORX PLUS geometry for driver compatibility.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the coating thickness increases on flutes, then corrosion protection is improved, but the flutes become less deep preventing proper insertion of drive tools and measuring gauges

Engineering Contradiction:

Improvecorrosion protectionVSAvoidflute depth

Core Design Contradiction:

ReliabilityVSLength of moving object

Solution Approach 1:

The punch pin is designed with pre-calculated dimensions that anticipate the coating deposition. The flutes are formed with initial depths and the lobes with specific radii that, after coating is applied, result in the correct final dimensions. This preliminary design action ensures that the coating process does not compromise the functional geometry.

Inventive Principle:

Principle #10Preliminary action

3Manufacturing precision

If the A dimension is increased to accommodate coating thickness, then drive tool fitment is maintained, but the overall socket size increases affecting fastener dimensions

Engineering Contradiction:

Improvedrive tool fitmentVSAvoidsocket size

Core Design Contradiction:

Manufacturing precisionVSVolume of moving object

Solution Approach 1:

Rather than uniformly increasing all socket dimensions, the invention applies dimensional adjustments locally to specific features. The lobes have different radii (first radius larger than second radius) and the flutes have specific depth modifications, allowing the socket to accommodate coating while maintaining overall compactness and fastener size constraints.

Inventive Principle:

Principle #3Local quality

Data Source

PatentEP3055576B1Punch pins, associated sockets, and methods of forming sockets using punch pins

Publication Date: 2021.01.20 ACUMENT INTELLECTUAL PROPERTIES LLC

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AI summary

Punch pins which have further extending lobes, and which are designed to punch sockets that have deeper flutes while not having lobes which extend further toward a center axis of the fastener. Using such a punch pin to form a socket in a fastener provides that the resulting socket has flutes which are deeper than they otherwise would be, without having to provide corresponding lobes which extend further toward the center axis of the socket. This extra deepness in the flutes helps to provide extra room for a coating to deposit.