Modular Log Construction Using Vertical Mortises and Splines

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Solution Overview

Problem

The existing piece-en-piece log construction method is costly and labor-intensive due to the need for fashioning vertical tenons into horizontal log members, requiring heavy equipment and skilled labor for assembly.

Innovation Solution

Instead of tenons, vertical mortises are cut into the ends of horizontal log members, and these are secured with splines into matching grooves on upright timber members, allowing for easier assembly and vertical movement due to shrinkage or settling forces without the need for heavy equipment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If vertical tenons are fashioned into horizontal log members, then structural integrity is achieved, but manufacturing costs and labor costs increase

Engineering Contradiction:

Improvestructural integrityVSAvoidmanufacturing costs

Core Design Contradiction:

StrengthVSEase of manufacture

Solution Approach 1:

Instead of projecting tenons from horizontal logs, the patent inverts the approach by cutting recesses (mortises) into the horizontal logs and inserting splines from the upright timbers into these recesses. This inversion simplifies the manufacturing process by eliminating the need to fashion complex tenons while maintaining structural integrity through the spline insertion system.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent extracts the securing function from the horizontal log members themselves (by removing the need for tenons) and relocates it to the upright timber members (which provide the splines). This extraction allows the horizontal logs to be simpler in form while the upright timbers承担 the complexity of the securing mechanism.

Inventive Principle:

Principle #2Taking out (Extraction)

2Stability of the object's composition

If vertical tenons are used to secure horizontal logs, then lateral movement is prevented, but heavy equipment and specialized skills are required for assembly

Engineering Contradiction:

Improvelateral movement preventionVSAvoidassembly complexity

Core Design Contradiction:

Stability of the object's compositionVSEase of operation

Solution Approach 1:

The patent inverts the traditional mortise-and-tenon approach by making the upright timbers (rather than horizontal logs) the active element that projects securing features. The splines protrude from upright timbers into recesses in horizontal logs, making assembly simpler while maintaining lateral stability.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent employs relatively short timber pieces for the splines rather than requiring full-length precision-matched tenons. These shorter spline pieces are easier to handle and install, reducing the need for heavy equipment and specialized skills during assembly.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Reliability

If horizontal logs are raised to full height of upright timbers, then tenons can be engaged into mortises, but labor costs and assembly time increase

Engineering Contradiction:

Improvejoint engagementVSAvoidassembly time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

By inverting who provides the projecting element (upright timbers instead of horizontal logs), the patent allows horizontal logs to be placed more easily without requiring precise height alignment with full upright timber height, thus reducing assembly time while ensuring reliable joint engagement through the spline system.

Inventive Principle:

Principle #13The other way round (Inversion)

4Ease of operation

If short timbers are used instead of long wall-length logs, then handling becomes easier, but additional components are required

Engineering Contradiction:

Improvehandling easeVSAvoidnumber of components

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The patent segments the wall construction into horizontal log members and separate spline components. The splines act as additional small segments that connect the horizontal logs to upright timbers, enabling easier handling of short timber pieces while maintaining structural integrity through modular assembly.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentUS8028480B2Modular log building construction

Publication Date: 2011.10.04 FIRST KASKA CONSTR LLP

AI summary

This application describes a wall construction and method of making the same in generally a Piece-en-piece mode. A vertical mortise is provided in adjacent vertical timber members and vertical mortises are cut into the end faces of horizontal timber members expected to be placed between adjacent vertical member. When the horizontal timber members are in place the vertical mortises align and wooden or metal splines can be inserted into the mortises thus securing the horizontal members laterally while still allowing them to move vertically to account for, for example, shrinkage in the wood. By substituting a mortise for a tenon, this invention reduces manufacturing costs and reduces assembly time and costs, as each horizontal timber can be set directly into place without lifting it to the top of the upright timber members.