Pivoting Bobbin Arms for Automatic Inflator Actuation
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Solution Overview
Problem
Automatic inflators for inflatable articles, such as life rafts and life vests, face issues with premature activation due to humidity in non-emergency situations and delayed actuation in cold water, as existing water-activated automatic inflators using dissolvable pills are not sufficiently resistant to humidity or effective in freezing conditions.
Innovation Solution
A humidity-resistant, cold-weather bobbin design with interconnected pivotal arms via webs, which allows paired arms to pivot outwardly in unison upon pill dissolution, releasing the spring-loaded actuator to actuate the pierce pin, reducing premature activation and improving firing speed in cold water.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If a dissolvable pill is used in a water-activated automatic inflator, then the inflator can be automatically activated upon immersion in water, but the pill tends to prematurely destruct when exposed to excessive humidity in the air
Solution Approach 1:
The bobbin is segmented into multiple pivotal arms (at least three arms radially spaced apart) that can independently pivot relative to the bobbin body. This segmentation allows the structure to respond differentially to water exposure, with water able to penetrate and dissolve the pill at multiple points simultaneously, accelerating actuation while maintaining humidity resistance through the pivotal arm mechanism that requires full water immersion to trigger complete dissolution and actuation.
2Reliability
If the pill is made more resistant to humidity, then premature activation is reduced, but the pill becomes too resistant to dissolving in cold water, leading to delayed actuations
Solution Approach 1:
The pivotal arms are designed to dynamically pivot from an initial position where they engage and hold the actuator pin in a cocked position to a second position where they release the actuator pin. This dynamic mechanism allows the structure to maintain reliability in humid conditions while enabling rapid actuation in cold water, as the pivotal movement amplifies the dissolution effect and accelerates the release mechanism when water immersion occurs.
3Device complexity
If conventional bobbin designs are used, then the structure is simple, but the firing time in freezing cold water is delayed (5.70-7.34 seconds)
Solution Approach 1:
The invention introduces a radial dimension to the dissolution process by arranging multiple pivotal arms radially spaced around the bobbin body. This radial configuration allows water to penetrate and dissolve the pill material at multiple locations simultaneously, creating a multi-dimensional dissolution front that accelerates the actuation process from 5.70-7.34 seconds to 1.92-2.01 seconds, while the pivotal arm mechanism adds a rotational degree of freedom that amplifies the release action.
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
The bobbin design significantly reduces premature activation in humid conditions and accelerates actuation in freezing cold water, achieving average firing times of 1.92-2.01 seconds compared to 5.70-7.34 seconds with prior art, ensuring quick and reliable inflation in emergency situations.
Implementation Method 1
Upon exposure to water, the dissolvable 'pill' contained within the bobbin immediately starts dissolving and then destructs altogether
Data Source
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AI summary
A bobbin assembly for an automatic inflator including a generally cylindrical wall; a plurality of arms positioned in a ring centered about and parallel to a longitudinal axis of the bobbin, each arm being pivotably connected to a rim of said cylindrical wall by a living hinge; at least one said arms including a radial seat extending toward said longitudinal axis of the bobbin to form an annular seat having a diameter to retain a head of a spring-loaded actuator pin of the automatic inflator to hold the spring-loaded actuator pin in a "cocked" position; a toroidal pill positioned between a lumen of said cylindrical wall and said ringed arms to retain said arms in position centered about and parallel to said longitudinal axis of the bobbin; and a web interconnecting at least one of adjacent pairs of said arms allowing said paired arms to pivot outwardly in unison.