Chain Joint With Variable Profile Cross Section

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Solution Overview

Problem

Existing chain locks made from round steel with constant cross-sections are expensive and wasteful due to the cutting of endless chains, resulting in low bending resistance and tensile strength, while maintaining predetermined outer dimensions.

Innovation Solution

The chain lock design features a base body with a smaller profile cross-section in the link curves and larger cross-section on longitudinal legs, including a blind threaded hole for the locking screw, allowing for increased bending resistance and tensile strength without altering outer dimensions, and can be produced without cutting waste from endless chains.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the base body is made of round steel with constant cross-section, then the manufacturing is simpler, but the bending resistance moment and tensile strength are insufficient

Engineering Contradiction:
Improvebending resistance momentVSAvoidprofile cross-section variation
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The base body is designed with different profile cross-sections at different locations: a larger cross-section in the longitudinal leg area to increase bending resistance moment, and a smaller cross-section in the link curve area to maintain flexibility and fit within outer dimension constraints. This local differentiation of structural properties resolves the contradiction between strength requirements and manufacturing simplicity.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The solution transitions from a constant cross-section design (one-dimensional uniformity) to a variable cross-section design (two-dimensional variation along the length). By introducing dimensional variation in the cross-sectional area along the longitudinal axis, the design achieves higher bending resistance where needed while maintaining overall compactness.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Strength

If the base body is made of round steel with constant cross-section, then the manufacturing process is simpler, but the tensile strength is reduced

Engineering Contradiction:
Improvetensile strengthVSAvoidprofile cross-section variation
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The longitudinal legs are equipped with enlarged profile cross-sections that provide increased tensile strength where the locking screw applies clamping force. The variable cross-section design allows concentration of material in high-stress regions while reducing material in low-stress link curve areas.

Inventive Principle:
Principle #3Local quality

3Strength

If the outer dimensions are increased to improve strength, then the bending resistance moment increases, but the chain lock cannot be used on the same pocket chain wheels

Engineering Contradiction:
Improvebending resistance momentVSAvoidcompatibility with pocket chain wheels
Core Design Contradiction:
StrengthVSAdaptability or versatility

Solution Approach 1:

The design concentrates the increased cross-sectional area locally in the longitudinal leg regions where strength is critical, while maintaining the outer dimensions (overall length, width, and height) within the predetermined limits required for compatibility with existing pocket chain wheels. This allows strength enhancement without compromising adaptability.

Inventive Principle:
Principle #3Local quality

4Ease of manufacture

If chain links are cut from endless chains, then the base body can be manufactured, but material waste increases

Engineering Contradiction:
Improvebase body productionVSAvoidraw material waste
Core Design Contradiction:
Ease of manufactureVSLoss of substance

Solution Approach 1:

The base body is designed with a variable profile cross-section that cannot be produced by simple bending of round steel. This parameter change in the cross-sectional geometry necessitates alternative manufacturing methods such as precision casting or forging, which allow near-net-shape production from ingots or blanks, thereby reducing material waste compared to cutting from endless chains.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2935974B1Chain joint for link chains
Publication Date: 2017.09.06 PEWAG AUSTRIA GMBH
  • EP2935974B1 patent drawingFigure 1~5

AI summary

In a chain joint (1) for link chains, having a main body (2) in the form of an oval chain link with two mutually parallel longitudinal legs (3, 4) which are connected to one another at their ends in each case via a rounded link portion (5, 6) and one of which has an interruption for forming a receiving opening (7) for the hooking-in of oval chain links into an internal opening (8) of the main body (2), said receiving opening being bounded at its ends by in each case one longitudinal leg section (4A, 4B), wherein, in said longitudinal leg (4), there is provided a threaded bore (9) which runs in the longitudinal direction of said longitudinal leg and which extends in both longitudinal leg sections (4A, 4B) and into which there can be screwed a closure screw (10) which, in the screwed-in state, engages with the threaded bore (9) in both longitudinal leg sections (4A, 4B), it is provided that, while maintaining the predefined sizes for outer circumference (A) and link width (B) of the main body (2), said main body is provided, in the region of its longitudinal legs (3, 4), with a profile cross section (Q1) that is larger than the profile cross section (Q2) in the region of its rounded link portions (5, 6).