Cotter Joint Guardrail Sections Quick Disassembly

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Solution Overview

Problem

Existing cotter joints in safety traffic barriers lack sufficient strength for quick disassembly, posing a health hazard due to their lower strength compared to screw connections, which complicates emergency vehicle access across barriers.

Innovation Solution

A cotter joint design featuring bolts with cross-sections matching guardrail mounting openings, reinforced plates on overlapping sections, and locking cotters that provide a secure and quick disassembly mechanism, enhancing strength and durability while maintaining cost-effectiveness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If screw connections are used to connect guardrail sections, then the connection strength is sufficient, but the disassembly process becomes complicated and time-consuming

Engineering Contradiction:
Improveconnection strengthVSAvoiddisassembly time
Core Design Contradiction:
StrengthVSLoss of time

Solution Approach 1:

The connection system is segmented into modular components: guardrail sections with mounting openings, bolts with transverse through holes, and locking cotters. This segmentation allows the connection to be quickly assembled and disassembled by simply inserting and removing the bolt-cotter assembly, eliminating the time-consuming nature of screw connections while maintaining structural integrity through the overlapping section design

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The connection system transitions from a static screw thread engagement to a dynamic insertion-removal mechanism. The bolt with transverse through hole and locking cotter creates a reversible connection that can be rapidly engaged and disengaged, enabling emergency vehicles to pass through by quickly removing the locking cotters and extracting the bolts, thus reducing disassembly time significantly

Inventive Principle:
Principle #15Dynamics

2Loss of time

If typical longitudinal mounting openings are used with cotter joints, then quick disassembly is enabled, but the connection strength becomes considerably lower than screw connections

Engineering Contradiction:
Improvedisassembly timeVSAvoidconnection strength
Core Design Contradiction:
Loss of timeVSStrength

Solution Approach 1:

The mounting openings are positioned in the overlapping section of adjacent guardrail sections rather than in the main body. This dimensional relocation to the overlap region allows the bolt to engage both sections simultaneously, creating a stronger connection that distributes loads across the overlapping area, thereby increasing connection strength while preserving quick disassembly capability

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

Solution Approach 2:

The connection system uses a composite approach combining multiple elements: the overlapping guardrail sections, the bolt with transverse through hole, and the locking cotter. This composite structure creates a synergistic effect where the overlapping sections provide structural reinforcement, the bolt provides precise alignment and load distribution, and the cotter provides secure locking, collectively achieving both high strength and quick disassembly

Inventive Principle:
Principle #40Composite materials

3Ease of operation

If bolts with transverse through holes are used in typical mounting openings, then quick disassembly is possible, but the connection strength is insufficient for safety requirements

Engineering Contradiction:
Improvedisassembly easeVSAvoidsafety reliability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The guardrail sections are pre-configured with overlapping ends and mounting openings positioned in the overlap region. This preliminary preparation ensures that when the bolt is inserted, it automatically engages both sections at optimized locations, creating a strong connection without requiring additional reinforcement or complex assembly steps, thus maintaining safety reliability while enabling easy disassembly

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The locking cotter acts as an intermediary element that secures the bolt in place after insertion. The cotter fits into the transverse through hole and prevents the bolt from disengaging, providing a reliable locked state that ensures safety during normal operation. For disassembly, the cotter can be quickly removed with simple tools, allowing rapid release while maintaining high reliability during service

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3553228B1A cotter joint of guardrail sections of a safety traffic barrier and a safety traffic barrier comprising such a cotter joint
Publication Date: 2020.12.23 STALPROD
  • EP3553228B1 patent drawingFigure 1~3
  • EP3553228B1 patent drawingFigure 4~8
  • EP3553228B1 patent drawingFigure 9~13

AI summary

The present invention relates to a cotter joint (1) of guardrail (2) sections (21) of a safety traffic barrier (5) comprising at least one bolt (3) having a transverse through hole (32) of a longitudinal axis (O3) nonparallel relative to the longitudinal axis (O2) of the bolt (3) and a resisting head (31), wherein the bolt (3) extends through mounting openings (223) of the connecting end sections (22) of the guardrail (2) sections (21) which overlap with each other and adjoin with each other by means of internal contact surfaces (221), wherein the mounting openings (223) correspond to each other and substantially coincide with each other, wherein the transverse through hole (32) of the bolt (3) is located at the side of the guardrail (2) sections (21) which overlap with each other, opposite relative to the resisting head (31), and a locking cotter (4) which is disposed in a transverse through hole (32) of the bolt (3) and tightens the guardrail (2) sections (21), which overlap with each other, against the resisting head (31) of the bolt (3). In order to provide an increased strength as well as a simple and cost-effective construction enabling a quick disassembly of such a cotter joint, the bolt (3) has a cross-section substantially corresponding to the cross-section of the mounting opening (223) of the guardrail (2) sections (21), and at least one reinforcing plate (224) is mounted on each external non-contact surface (222) of connecting end sections (22) of the guardrail (2) sections (21) which overlap with each other, wherein the reinforcing plate (224) is provided with at least one through hole (225) substantially coincided with the at least one mounting opening (223) of the guardrail (2) section (21) to which this reinforcing plate (224) is mounted.