Breathing Regulator Bypass Knob With Torque-Limiting Feedback

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Solution Overview

Problem

Existing bypass assemblies for breathing apparatus pressure regulators do not provide positive feedback when fully closed and lack torque limiting mechanisms, leading to potential misuse or damage.

Innovation Solution

A bypass knob with a deflectable beam mechanism that provides tactile and auditory feedback when fully closed, and limits torque to prevent over-tightening, ensuring secure closure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of information

If a threaded knob bypass assembly is used, then the bypass assembly can be operated between fully open and fully closed positions, but no positive feedback is provided to indicate when the bypass assembly is fully closed

Engineering Contradiction:
Improvefeedback indicationVSAvoidbypass assembly structure
Core Design Contradiction:
Loss of informationVSDevice complexity

Solution Approach 1:

The patent implements a feedback mechanism through a detent mechanism with a ball and detent groove. When the bypass knob reaches the fully closed position, the ball engages with the detent groove to provide tactile and auditory feedback, confirming to the user that the bypass assembly is properly closed. This resolves the information loss by providing clear positional indication without significantly complicating the overall device structure.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent incorporates visual feedback through a window and indicator mechanism. When the bypass assembly is in the fully closed position, the indicator aligns with the window to display a visual confirmation (such as an arrow or marker alignment). This provides additional information feedback to the user about the bypass assembly status, complementing the tactile feedback from the detent mechanism.

Inventive Principle:
Principle #32Color changes

2Reliability

If no torque limiting mechanism is provided, then the threaded knob can be freely rotated, but over-tightening may occur causing damage or misuse

Engineering Contradiction:
Improveprevention of damageVSAvoidknob rotation freedom
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The patent employs a preliminary anti-action approach through the detent mechanism that physically prevents further rotation of the bypass knob beyond the fully closed position. The ball-deten groove engagement creates a mechanical stop that counteracts any excessive tightening force, protecting the bypass assembly and connected components from damage while still allowing free rotation within the operational range.

Inventive Principle:
Principle #9Preliminary anti-action

Solution Approach 2:

The bypass knob mechanism incorporates dynamic elements including the movable ball within the detent groove and spring-loaded components that allow smooth rotation during normal operation. The system transitions from a static rigid connection to a dynamic mechanism with controlled movement, enabling ease of operation while preventing over-tightening through the engineered detent engagement points.

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

Ensures the bypass assembly is securely closed with positive feedback, preventing damage and misuse while maintaining operational safety.

Implementation Method 1

at least one deflectable beam is provided on the second engagement surface of the second member. The at least one deflectable beam has a first end connected to the second member and a second, free end opposite the first end

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3897872B1Bypass knob for breathing apparatus pressure regulator
Publication Date: 2025.08.06 MSA TECHNOLOGY LLC
  • EP3897872B1 patent drawingFigure 1~2
  • EP3897872B1 patent drawingFigure 3~4
  • EP3897872B1 patent drawingFigure 5

AI summary

A bypass knob for a pressure regulator configured for use with a facemask of a breathing apparatus has a first member having a first engagement surface and a second member having a second engagement surface positioned opposite the first engagement surface. At least one slot is formed on the first engagement surface and at least one deflectable beam having a latch is formed on the second engagement surface of the second member. When the first member is rotated in a first direction about the longitudinal axis via a first rotational torque, the latch of the at least one deflectable beam is engaged with the at least one slot to rotate the second member with the first member, and disengaged when the first member is rotated in the first direction via a second rotational torque higher than the first rotational torque.