Self-locking Cylindrical Assembly with V-shaped Recesses

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Solution Overview

Problem

Existing self-locking cylindrical assemblies, such as pins or bolts, face issues with reliability due to the degradation of elastic components like rubber under weather conditions and the presence of protruding parts that can cause hooking or injury, making them difficult to repeatedly insert and remove without tools.

Innovation Solution

A self-locking cylindrical assembly with a hollow bush featuring a broad internal seat, a narrow internal area, and an actuating rod with a compression spring and V-shaped guiding recesses for radially displaceable arresting sliders, allowing secure insertion and removal without tools, while minimizing protruding components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If elastic components like rubber are used for self-locking functionality, then the assembly can be easily inserted and removed without tools, but the reliability deteriorates due to degradation under weather conditions and repeated use

Engineering Contradiction:
Improvetool-free insertion and removalVSAvoiddurability under weather conditions
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent removes the elastic component (rubber) entirely from the system. Instead of using rubber elasticity for the self-locking mechanism, the invention employs a purely mechanical solution with spring-loaded arresting sliders that are actuated by a compression spring and cam mechanism, eliminating the reliability issues associated with rubber degradation.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the durable but problematic elastic rubber component with a mechanical system using spring elements and metal sliders. This mechanical system is designed to be more durable and resistant to environmental factors, sacrificing the simplicity of elastic deformation for long-term reliability.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

2Reliability

If protruding components like arresting arms are used for security, then the assembly is firmly protected against undesired removal, but harmful factors increase due to hooking risks and injury potential

Engineering Contradiction:
Improvesecurity against undesired removalVSAvoidhooking and injury risk
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent removes the external protruding arresting arm from the system. Instead of having an arm that protrudes outward to engage with the bore, the invention uses internal spring-loaded sliders that remain retracted within the bush until actuated, eliminating the hooking and injury risks while maintaining the security function.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent inverts the traditional approach by having the locking elements (arresting sliders) remain internal and retracted by default, rather than protruding outward. The locking action is achieved by the sliders being forced outward by spring pressure when the pin is inserted, rather than by an external arm being actively engaged.

Inventive Principle:
Principle #13The other way round (Inversion)

3Ease of operation

If elastic members like rubber membranes are used for actuating mechanisms, then the assembly can be operated by single hand without tools, but device complexity increases due to potential damage and plastic deformation

Engineering Contradiction:
Improvesingle-hand operationVSAvoidvulnerability to damage and deformation
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent removes the elastic rubber membrane from the actuating mechanism. Instead of using a rubber membrane that can be stretched and deformed, the invention employs a rigid compression spring and cam mechanism that actuates the arresting sliders, eliminating the vulnerability to plastic deformation while maintaining single-hand operation capability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the elastic membrane-based actuating system with a mechanical spring-cam system. This substitution provides more reliable and repeatable actuation without the degradation issues associated with elastic materials, while still allowing for simple manual operation.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The assembly provides reliable, tool-free insertion and removal of the pin or bolt, maintaining security against undesired removal and reducing the risk of hooking or injury from protruding parts, with improved durability due to the absence of elastic components prone to damage.

Implementation Method 1

an actuating rod, which is on its first end portion interconnected with an actuating button and surrounded by a compression spring, by which said actuating button can be pushed along said central axis towards said broader end portion

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

two V-shaped guiding recesses, which are open towards the exterior and converge towards said broader end portion and diverge towards the opposite end portion and are adapted to guide two radially displaceable arresting sliders

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP2912326B1Self-locking cylindrical assembly
Publication Date: 2017.05.31 TAJFUN PLANINA PROIZVODNJA STROJEV D O O
  • EP2912326B1 patent drawingFigure 1~2
  • EP2912326B1 patent drawingFigure 3
  • EP2912326B1 patent drawingFigure 4~5

AI summary

The invention refers to a long-term usable i.e. repetitively usable cylindrical assembly without any outwardly protruding parts, which could involve problems, wherein said assembly is insertable into each available bore (19', 19") or similar passage, in which it is automatically locked and reliably secured against undesired removal, but when desired, it can also be easily removed from said bore (19', 19") by means of a single hand and without any need on using a tool. The proposed assembly comprises a hollow cylindrical bush (1) having a broader first end portion (11) with an external seat (110) and a second end portion (12) furnished with two radial passages (121, 122) which are adapted to receive radially displaceable arresting sliders (16', 16") and an actuating rod (14), which is inserted within said bush (1) and is displaceable to and fro along the central axis (100) of said bush (100). The actuating rod (14) is on its opposite end portion (12) furnished with a centrally arranged and towards the axis (100) extending elongated hole (143), which is adapted to guide said actuating rod (14), as well as with two guiding recesses (144', 144"), which are open towards the exterior and positioned in a V-shaped arrangement converging thereby towards the broad end portion (11) of the bush (1) and diverging towards the opposite end portion (12) of the bush (1) and are moreover adapted to cooperate with protrusions (160', 160") of the arresting sliders (16', 16'), which are radially displaceable within said passages (121, 122) in said bush (1), wherein said recesses (144', 144".) are on both end portions thereof furnished with run-outs (1441', 1441"; 1442', 1442") extending parallel to said central axis (100) of the bush (1).