Wood Screw Rib Structure to Prevent Splitting in Timber

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Solution Overview

Problem

Wood screws often cause splitting and surface damage when penetrating wooden elements, weakening their load-bearing capacity and reducing construction quality.

Innovation Solution

A wood screw design featuring ribs between thread flanks, which engage the wood material only after initial penetration, minimizing splitting force and creating an insertion channel without fiber compaction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a wood screw is used to penetrate wooden elements, then a reliable connection is achieved, but splitting and surface damage occur compromising wood quality

Engineering Contradiction:
Improveconnection reliabilityVSAvoidwood splitting and surface damage
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The rib structure is provided in advance on the screw shaft before screwing operation. This preliminary structural arrangement allows the rib to automatically engage and remove wood material as the screw penetrates, preventing fiber compaction and splitting before they can occur. The rib acts as a pre-positioned material removal element that activates during the screwing process.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The screw structure is segmented into distinct functional zones: the rib portion for material removal and channel creation, and the thread portion for securing and anchoring. This segmentation allows each element to perform its specific function optimally - the rib handles fiber separation without compaction while the threads provide mechanical interlocking.

Inventive Principle:
Principle #1Segmentation

2Object-affected harmful factors

If cutting ribs are added to prevent splitting, then wood quality is preserved, but device complexity increases

Engineering Contradiction:
Improvewood splitting preventionVSAvoidscrew structure complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The rib structure is merged with the screw shaft as an integrated feature rather than a separate component. The rib is formed directly on the shaft surface between thread flanks, combining the fastening function (threads) and the fiber-protection function (rib) into a single unified element, thereby avoiding additional parts while preventing wood splitting.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The rib structure is applied locally only in the region where fiber compaction and splitting are most likely to occur during initial penetration. The rib is positioned between thread flanks at a specific location on the shaft, providing targeted protection exactly where needed without requiring complex modifications throughout the entire screw structure.

Inventive Principle:
Principle #3Local quality

3Object-affected harmful factors

If the rib removes wood material to prevent compaction, then splitting is avoided, but manufacturing precision requirements increase

Engineering Contradiction:
Improvefiber compaction avoidanceVSAvoidrib positioning and geometry precision
Core Design Contradiction:
Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The rib geometry parameters (height, width, angle) are optimized to achieve effective material removal without requiring extreme manufacturing precision. By adjusting these parameters within reasonable ranges, the rib can successfully separate wood fibers and prevent compaction while maintaining manufacturability with standard tolerances.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP3401557B2Wood screw
Publication Date: 2025.08.27 PROFIX AG
  • EP3401557B2 patent drawingFigure 1~2
  • EP3401557B2 patent drawingFigure 3(a)~(5l)

AI summary

The invention relates to a wood screw for screwing at least one wooden element. The wood screw has a shank (1) which has a screw head (2) at the rear end of the shank and a tapering front end (3). A screw thread (5) extends from a tip (4) of the front end (3) over at least part of the shank (1) towards the screw head (2). In the area of ​​the front end (3), at least one rib (6, 6") is provided between thread flanks (5, 5") of the screw thread (5). The at least one rib (6, 6") is only provided in the thread after at least one thread length of the screw thread (5).