Automatically Locking Linear Actuator with Integrated Rotary Lock

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Solution Overview

Problem

Conventional linear actuators require separate lock mechanisms and actuation systems, increasing complexity and cost due to the need for dedicated control devices and wiring/hydraulic tubing for locking and unlocking functions.

Innovation Solution

An automatically locking actuator design featuring a rotatable drive screw, nut assembly, rotary lock with key assemblies, and a lost motion connector that allows initial rotation of the rotary lock to unlock the actuator before axial movement, eliminating the need for a separate lock driver by integrating locking and unlocking within the actuator's operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a separate lock mechanism and actuation system are used, then the locking and unlocking functions are reliable, but the device complexity and cost increase due to dedicated control devices and wiring/hydraulic tubing

Engineering Contradiction:
Improvelocking function reliabilityVSAvoidactuator complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the locking mechanism and the drive mechanism into a single integrated system. The lock sleeve is mechanically coupled to the drive screw and nut assembly, allowing the drive mechanism to automatically perform the locking function during retraction without requiring a separate lock actuator. This merging eliminates dedicated control devices and reduces wiring/hydraulic tubing while maintaining reliable locking functionality.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The drive mechanism serves multiple functions: it provides both the driving force for ram movement and the automatic locking action. The lock sleeve acts as a universal component that engages with both the drive mechanism and the ram, performing both locking and positioning functions simultaneously. This multi-functionality reduces the need for separate dedicated components.

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

2Ease of operation

If a separate lock driver actuator is used, then the locking control is precise, but the weight and size of the actuator increase

Engineering Contradiction:
Improvelocking control precisionVSAvoidactuator weight
Core Design Contradiction:
Ease of operationVSWeight of moving object

Solution Approach 1:

The patent merges the lock driver functionality into the existing drive mechanism. The lock sleeve is integrated with the drive screw and nut assembly, eliminating the need for a separate lock driver actuator. The drive mechanism itself provides the precise control needed for locking by controlling when and how the lock sleeve engages with the ram during retraction.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent extracts the separate lock driver actuator from the system entirely, removing unnecessary weight and size. The locking function is achieved through the existing drive components working in coordination, specifically the lock sleeve that is mechanically linked to the drive mechanism rather than requiring an independent actuator.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If a separate lock driver actuator is used, then the locking function is independent, but the number of parts and cost increase

Engineering Contradiction:
Improvelocking independenceVSAvoidnumber of parts
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent combines the locking function with the drive mechanism, eliminating the need for a separate lock driver actuator and its associated components. The lock sleeve is integrated into the drive assembly, sharing mechanical linkages with the drive screw and nut. This reduces the total number of parts while maintaining independent locking capability through the mechanical coupling between drive and lock components.

Inventive Principle:
Principle #5Merging (Combining)

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

This design reduces the weight and size of the actuator, simplifies control, and allows for self-locking and unlocking, minimizing the number of parts required and enhancing operational efficiency by integrating locking and unlocking functions within the actuator's mechanism.

Implementation Method 1

a rotatable drive screw operably coupled to the first end connector, a nut assembly threadably mounted on the drive screw, a second end connector operably coupled to the nut assembly

Methodology Applied
Scientific EffectScrew mechanism: Screw

Implementation Method 2

a lost motion connector rotationally coupling the nut assembly to the rotary lock such that rotation of the drive screw results in an initial rotation of the nut assembly and rotor to move the key assembly between the extended and retracted positions prior to axial movement of the nut assembly along the drive screw

Methodology Applied
Scientific EffectLost motion mechanism: Backlash

Implementation Method 3

a rotary lock comprising a rotor and at least one key assembly that moves between extended and retracted positions in response to rotation of the rotor

Methodology Applied
Scientific EffectRotational actuation:

Data Source

PatentEP2604514B1Automatically locking linear actuator
Publication Date: 2018.10.03 WOODWARD HRT INC
  • EP2604514B1 patent drawingFigure 1
  • EP2604514B1 patent drawingFigure 2
  • EP2604514B1 patent drawingFigure 3

AI summary

An automatically locking actuator (10) includes a first end connector (12), a rotatable drive screw (16) operably coupled to the first end connector (12), a nut assembly (18) threadably mounted on the drive screw (16), a second end connector (14) operably coupled to the nut assembly (18) and a rotary lock (20) having a rotor (22) and where the actuator (10) moves between extended and retracted positions in response to rotation of the rotor (22).