Telescopic Actuator Locking With Elastic Blade Obstacles

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Solution Overview

Problem

Existing telescopic actuators often rely on a locking piston for locking and unlocking mechanisms, which can malfunction, preventing the rod from being positively locked in place.

Innovation Solution

A telescopic actuator design featuring radially movable obstacles that automatically engage with a groove on the rod to lock it in place, eliminating the need for a locking piston, with controlled blade bending mechanisms for unlocking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a locking piston is used to lock the rod in position, then the rod can be locked in the cylinder, but the locking mechanism may malfunction and fail to positively lock the rod

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

Solution Approach 1:

The invention removes the locking piston from the system entirely. Instead of using a piston-based locking mechanism, the patent employs elastic blades with hooks that automatically engage with the rod through purely mechanical means, eliminating the complex piston assembly and its associated control systems while maintaining reliable locking functionality.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The elastic blades are designed to automatically engage and disengage from the rod without external control. The blades utilize their own elasticity to flex outward for engagement and return inward for disengagement, making the locking mechanism self-actuating and eliminating the need for piston-driven control.

Inventive Principle:
Principle #25Self-service

2Ease of operation

If a locking piston is used to control the locking members, then individual control of locking is achieved, but the mechanism becomes more complex and prone to malfunction

Engineering Contradiction:
Improvelocking controlVSAvoidpiston control system
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The elastic blades automatically perform the locking and unlocking functions based on the position of the rod. When the rod moves into the locked position, the blades naturally flex outward and engage with the rod's groove. When the rod moves away, the blades automatically retract. This self-service mechanism eliminates complex control systems while maintaining ease of operation.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The invention combines the locking function with the rod's own movement. The rod's axial displacement directly controls the engagement of the elastic blades, merging the locking action with the rod's operational movement rather than requiring a separate control system.

Inventive Principle:
Principle #5Merging (Combining)

3Ease of operation

If slopes are provided on contact parts to allow locking members to be pushed back, then unlocking is enabled, but the locking members may not be reliably held in the locked position

Engineering Contradiction:
Improveunlocking mechanismVSAvoidlocking member retention
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The invention uses curved engagement surfaces between the elastic blade hooks and the rod's groove. The concave profile of the groove and the corresponding shape of the hooks create a self-centering engagement that reliably holds the locked position while still allowing controlled disengagement when the rod moves, eliminating the need for separate unlocking slopes.

Inventive Principle:
Principle #14Spheroidality (Curvature)

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

Ensures reliable automatic locking and unlocking of the rod without a locking piston, enhancing the actuator's stability and operational efficiency by preventing malfunctions associated with piston-based systems.

Implementation Method 1

the obstacles being arranged at the end of elastic blades extending axially and arranged to recall the obstacles from the retracted position to the projecting position

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3569873B1Telescopic actuator with automatic locking
Publication Date: 2021.09.22 SAFRAN LANDING SYSTEMS
  • EP3569873B1 patent drawingFigure 1
  • EP3569873B1 patent drawingFigure 2
  • EP3569873B1 patent drawingFigure 3

AI summary

The invention relates to a telescopic actuator comprising a cylinder (1) having a closed end (2) and an open end (3) for the passage of a hollow rod (4) mounted to slide axially in the cylinder.The actuator includes a central support (10) extending from the closed end of the cylinder inside the rod and carrying radially movable obstacles (15) between a retracted position allowing free sliding of the rod and a protruding position in which the obstacles are engaged in a groove (9) of the rod to axially lock the rod relative to the cylinder, the flanks of the obstacles and of the groove being shaped to prevent any withdrawal of the obstacles by displacement of the rod, the obstacles being disposed at the end of elastic blades (14) extending longitudinally and arranged to recall the obstacles from the retracted position to the protruding position, the central support carrying controlled means (20) for bending the blades to cause the withdrawal of the obstacles to the retracted position.