Linear Adjuster Stop Locking for Reliable Travel Limits

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Solution Overview

Problem

Existing linear adjusters face challenges in ensuring reliable operation and efficient adjustment, particularly in preventing unintended movement beyond desired stop positions during retraction and extension movements.

Innovation Solution

The linear adjuster incorporates a locking device that allows for a stop-ready state and a stop-release state, enabling controlled movement by mechanically fixing or releasing the stop devices, and includes a spindle-spindle nut mechanism for precise adjustment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the stop devices are mechanically fixed to prevent movement beyond stop positions, then the reliability of the linear adjuster is improved, but the ease of operation deteriorates due to the need for locking and releasing mechanisms

Engineering Contradiction:
Improvereliable operationVSAvoidease of operation
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The stop devices are pre-positioned at predetermined locations along the adjustment path. The locking device is designed to automatically engage with these pre-positioned stops at specific adjustment positions, eliminating the need for manual intervention to prevent over-travel. This preliminary positioning of stop elements ensures reliable operation while maintaining ease of use.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The locking device automatically engages with the stop devices when the linear adjuster reaches predetermined adjustment positions during extension or retraction. This self-activating mechanism prevents movement beyond stop positions without requiring user action, thereby improving reliability while preserving ease of operation. The system serves itself by automatically locking at appropriate positions.

Inventive Principle:
Principle #25Self-service

2Reliability

If the locking device is added to mechanically fix the stop devices, then the reliability is improved, but the device complexity increases

Engineering Contradiction:
Improvereliable operationVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The locking device is integrated with the existing spindle-spindle nut mechanism and stop devices. The locking components are combined with the adjustment mechanism such that the same structural elements serve multiple functions: the spindle-spindle nut mechanism provides adjustment motion while the integrated locking device provides automatic positioning and prevention of over-travel. This merging reduces overall system complexity compared to adding separate independent locking systems.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The locking device is designed to work with both the extension and retraction movements of the linear adjuster using the same mechanical principles and components. The stop devices and locking mechanism serve multiple functions: they define adjustment limits, provide mechanical feedback, and prevent damage from over-travel in both directions. This multi-functionality reduces the need for separate specialized components.

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

3Reliability

If the stop devices are positioned to prevent further movement during retraction, then the reliability is improved, but the adjustment range is reduced

Engineering Contradiction:
Improvereliable operationVSAvoidadjustment range
Core Design Contradiction:
ReliabilityVSLength of moving object

Solution Approach 1:

The stop devices are positioned at predetermined locations along the adjustment path, allowing the linear adjuster to dynamically achieve full adjustment range during normal operation. The locking mechanism only activates when the adjuster reaches these predetermined stop positions, preventing over-travel while maintaining the full intended adjustment range between stops. This dynamic approach allows maximum useful adjustment while providing protective limits.

Inventive Principle:
Principle #15Dynamics

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 ensures reliable operation by preventing further movement beyond predetermined positions, allowing for precise adjustment and repair of the linear adjuster, enhancing its functionality and reliability.

Implementation Method 1

The linear adjuster (1) has a spindle-spindle nut mechanism (2) with a spindle (3) and a spindle nut (5)

Methodology Applied
Scientific EffectScrew mechanism: Screw

Implementation Method 2

The locking device (50) fixes the first stop device (30) in a stop-ready state

Methodology Applied
Scientific EffectMechanical fixation: Mechanical Fastener

Data Source

PatentEP4139587B1Linear adjuster, positioning device, positioning assembly and method for repairing a linear adjuster
Publication Date: 2025.08.20 PHYSIK INSTRUMENTE (PI) GMBH & CO KG
  • EP4139587B1 patent drawingFigure 1~2
  • EP4139587B1 patent drawingFigure 3
  • EP4139587B1 patent drawingFigure 4

AI summary

The invention relates to a linear adjuster (1), comprising: - a spindle-and-spindle-nut mechanism (2); - a first adjustment part (10), which has a first main body (11) and a first stop device (30); - a second adjustment part (20), which has a second main body (21) and a second stop device (40), wherein the first adjustment part (10) and the second adjustment part (20) can be moved relative to each other by means of a spindle-and-spindle-nut mechanism (2) having a spindle longitudinal axis (L3), and wherein the first stop device (30) and the second stop device (40) come to a stop state when the linear adjuster (1) performs a retraction travel movement or an extension travel movement and the first adjustment part (10) and the second adjustment part (20) are in a predefined stop travel position relative to each other. The invention also relates to a positioning device, to a positioning assembly and to a method for repairing a linear adjuster (1).