Gas Spring Safety Device with Pre-Strike Member

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Solution Overview

Problem

Existing safety devices in compressible fluid devices, such as gas springs, are prone to accidental triggering, particularly when the gas springs are relieved of fluid pressure and subjected to loads, leading to overstroke issues that can cause damage and reduce the device's lifespan.

Innovation Solution

A safety device with a pre-strike member that is struck before the safety member, ensuring that the safety member is only engaged after a predetermined compressive overstroke force is reached, thereby preventing accidental triggering and allowing controlled fluid evacuation through a vent channel.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the safety member is positioned to be struck by the piston during overstroke, then fluid evacuation and protection are achieved, but accidental compression during service may trigger the safety device

Engineering Contradiction:

Improveoverstroke protectionVSAvoidaccidental triggering

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

Different parts of the safety device have different geometric properties and contact characteristics. The pre-strike member has a larger surface area and extends further radially, making it contact the piston first at lower forces. The safety member has a smaller contact area and is positioned to only engage at higher compression forces, creating locally differentiated response thresholds.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The device utilizes changes in compression force parameters to differentiate between service operations and overstroke events. The pre-strike member engages at lower force parameters during normal service, while the safety member only engages when compression forces exceed a higher threshold indicative of overstroke conditions.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the pre-strike member extends further inwardly from the chamber wall, then it contacts the piston before the safety member, but the device complexity increases

Engineering Contradiction:

Improvepre-strike functionalityVSAvoidsafety device structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The pre-strike member and safety member are combined into a single integrated safety device assembly that is mounted together in the bottom wall of the compression chamber. This merging approach allows both functional elements to work in sequence within a unified structure, reducing overall device complexity compared to having separate independent systems.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The pre-strike member and safety member are nested within the same mounting structure in the chamber wall. The pre-strike member is positioned to protrude further into the compression chamber, while the safety member is nested behind it, creating a layered arrangement that achieves the desired sequential contact without requiring separate mounting locations.

Inventive Principle:

Principle #7Nested doll (Nesting)

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 significantly reduces the risk of accidental triggering and ensures controlled fluid evacuation, protecting the gas spring and associated equipment from overstroke damage while maintaining effective protection against overstrkes.

Implementation Method 1

The pre-strike member may comprise a portion which is arranged to be deformed when struck with a predetermined force

Methodology Applied

Scientific EffectDeformation: Deformation

Implementation Method 2

a safety member in such a manner as to be struck by the piston in the event of the piston overstriking, whereby at least some of the compressible fluid is evacuated from the compression chamber

Methodology Applied

Scientific EffectFluid evacuation:

Data Source

PatentEP3314144B1Compressible fluid device comprising safety device and method of protecting a compressible fluid device

Publication Date: 2020.01.01 STROMSHOLMEN AB

Figure 1a~1b
Figure 1c~1d
Figure 2a~2d

AI summary

The present disclosure provides a compressible fluid device (1), such as a gas spring. The device comprises a casing (11) defining a compression chamber (12), a piston (15), which is movable in the chamber (12), and a safety member (2) placed in such a manner as to be struck by the piston (15) in the event of the piston overstriking, whereby at least some of the compressible fluid is evacuated from the compression chamber (12). The device further comprises a pre-strike member (25), that is arranged to be struck before the safety member (2) is struck, such that the safety member (2) is only struck once a predetermined overstroke force has been achieved.