Multi-Unit Rod Locking Structure for High Thrust Force

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Solution Overview

Problem

Existing locking devices for rods struggle to provide a simple structure that can exert a large locking force, especially when dealing with rods that have high thrust forces.

Innovation Solution

The locking device features multiple locking units with a single elongated lid that covers all casings, providing a single release port and multiple communication channels to increase locking force proportionally with the number of units. Each locking unit has annular stepped recesses and a connection spacer for accurate alignment and increased locking force.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If the material or thickness of the locking member is increased to increase elastic force, then the locking force is improved, but the device complexity and manufacturing difficulty increase

Engineering Contradiction:
Improvelocking forceVSAvoidstructure complexity
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

The locking device is divided into multiple independent locking units (first locking unit, second locking unit, etc.), each with its own locking member. By distributing the locking force requirement across multiple segments, each locking member can maintain a simple structure while the cumulative locking force increases proportionally with the number of units.

Inventive Principle:
Principle #1Segmentation

2Force

If a mechanism is provided to urge the locking member in the clamping direction, then the locking force is improved, but the device complexity increases

Engineering Contradiction:
Improvelocking forceVSAvoidmechanism complexity
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

The locking members are designed to be self-urging through their own elastic properties. Each locking member naturally exerts clamping force on the rod without requiring external urging mechanisms. The elastic force is generated intrinsically by the locking member's material and geometry, eliminating the need for additional complex mechanisms.

Inventive Principle:
Principle #25Self-service

3Force

If multiple locking units are used to increase locking force proportionally, then the locking force is improved, but the device complexity increases

Engineering Contradiction:
Improvelocking forceVSAvoidnumber of components
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

Multiple locking units share common components: a single elongated lid covers all locking unit casings, providing both the release port and all communication channels for multiple units. The connection spacers are identical and can be manufactured as standard components. This merging of common elements across multiple units increases locking force while minimizing the increase in overall complexity.

Inventive Principle:
Principle #5Merging (Combining)

4Force

If the friction force at the clamping surfaces is increased, then the locking force is improved, but the manufacturing precision requirements increase

Engineering Contradiction:
Improvelocking forceVSAvoidclamping surface precision
Core Design Contradiction:
ForceVSManufacturing precision

Solution Approach 1:

Instead of increasing friction force through surface treatment or material changes that would require high manufacturing precision, the invention increases locking force by changing the parameter of the number of locking units. This approach achieves higher locking force through a simple quantitative increase rather than qualitative changes to surface properties.

Inventive Principle:
Principle #35Parameter changes

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 allows for a locking force that is significantly larger than traditional devices with a single locking unit, making it easier to achieve the required locking force by adjusting the number of locking units based on the rod's thrust force.

Implementation Method 1

a first coil spring arranged in a case with its terminal end fixed to the case and its front end in a free condition. A locked rod is inserted through the inside of the first coil spring in the state of being fastened and locked with the spring force of the coil spring

Methodology Applied
Scientific EffectElastic force: Elasticity

Data Source

PatentEP3945220B1Locking device for a rod
Publication Date: 2025.04.30 SMC CORP
  • EP3945220B1 patent drawingFigure 1
  • EP3945220B1 patent drawingFigure 2
  • EP3945220B1 patent drawingFigure 3

AI summary

[Object] To provide a locking device having a simple structure and a large locking force. [Solution] A locking device includes multiple locking units 2 that are arrayed along the rod R. The locking units 2 each have a casing 4 through which the rod R is inserted and a lid 5 that covers the casing 4. The casing 4 accommodates a locking member 6 that clamps and thereby locks the rod R and a release piston 15 that unlocks the locking member 6 by receiving fluid pressure. A release pressure chamber 17 is formed between the release piston 15 and the lid 5 so as to apply the fluid pressure to the release piston 15. A release port 18 and a communication channel 19 that communicates the release port 18 with the release pressure chamber 17 are formed in the lid 5.