Locking Sleeve Assembly for Telescoping Hold Open Rods

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Solution Overview

Problem

Existing telescoping hold open rods lack effective mechanical features to maintain the rod in an open position under compressive loads, leading to unintended collapse and lack of user control over locking and unlocking operations.

Innovation Solution

A controllable locking sleeve assembly with a spiral radial retaining ring, torsion spring, and ball bearings that allow the telescoping rod to be locked in an extended position and unlocked for collapse, using a pin and slot mechanism for controlled movement and load distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a telescoping hold open rod uses discreet mechanical locking features (such as removable pins in holes), then the rod can be locked in an open position, but the locking mechanism becomes complex and requires precise alignment of multiple components

Engineering Contradiction:
Improvelocking reliabilityVSAvoidlocking mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The locking mechanism is segmented into a locking sleeve with multiple locking positions and corresponding locking features distributed along the rod. Each locking position has its own locking feature that engages with the sleeve, allowing the rod to be locked at various positions without requiring a single complex locking mechanism.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The locking function is extracted from the main rod structure and implemented through a separate locking sleeve that can independently engage with multiple locking positions. This separates the locking mechanism from the rod's primary function and allows for simpler, more reliable locking without complicating the overall rod design.

Inventive Principle:
Principle #2Taking out (Extraction)

2Ease of operation

If a telescoping hold open rod uses friction pads between the lock body and inner tube, then the rod can maintain position through friction, but the friction mechanism is insufficient under compressive loads causing unintended collapse

Engineering Contradiction:
Improverod positioning easeVSAvoidposition holding reliability under compressive load
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The locking mechanism transitions from a static friction-based system to a dynamic positive locking system. The locking sleeve can be actively moved to engage or disengage locking features, providing reliable locking under compressive loads while maintaining ease of operation through simple sleeve movement rather than requiring precise friction control.

Inventive Principle:
Principle #15Dynamics

3Reliability

If a telescoping hold open rod uses a removable pin for locking, then the rod can be locked in an open position, but the user lacks control over when the rod locks or unlocks

Engineering Contradiction:
Improvelocking reliabilityVSAvoiduser control over locking/unlocking
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The locking mechanism is designed to be self-servicing through the locking sleeve, which the user can directly manipulate to engage or disengage locking features. The sleeve's movement automatically controls the locking and unlocking actions, providing user control without requiring separate manual insertion or removal of pins.

Inventive Principle:
Principle #25Self-service

4Reliability

If a telescoping hold open rod uses multiple discrete locking components, then the rod can be locked in position, but the manufacturing and assembly precision requirements increase

Engineering Contradiction:
Improvelocking reliabilityVSAvoidalignment precision of locking features
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The locking sleeve serves multiple functions: it engages with multiple locking positions, provides the locking action, and controls the unlocking process. This multi-functional design reduces the need for multiple discrete locking components and their associated alignment requirements, simplifying manufacturing while maintaining reliable locking.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 solution ensures the rod remains securely open under compressive loads, preventing unintended collapse and allowing controlled extension and collapse, enhancing user access to panels while maintaining structural integrity.

Implementation Method 1

a spring coupled to the locking sleeve and the outer tube

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

ball bearings that allow the telescoping rod to be locked in an extended position and unlocked for collapse, using a pin and slot mechanism for controlled movement and load distribution

Methodology Applied
Scientific EffectMechanical Force distribution: Force

Data Source

PatentEP2914793B1Hold open rod locking sleeve
Publication Date: 2021.07.07 HARTWELL CORP
  • EP2914793B1 patent drawingFigure 1~2
  • EP2914793B1 patent drawingFigure 3~4
  • EP2914793B1 patent drawingFigure 5

AI summary

The present disclosure includes a telescoping hold open rod which is controllably lockable and unlockable for use in holding a panel such as a nacelle open to provide a user access to an opening covered by the panel. The hold open rod is useful in allowing the rod to be unlocked and telescopically collapsed. The rod can be locked into a telescopically extended position to maintain the panel in an open position relative to the opening to facilitate access to the opening without the rod telescoping closed. A retention assembly includes structures and devices to maintain the rod in an open condition although subject to compressive loads.