Hermetic Sealing for Locking Retractor Spool Shafts
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Solution Overview
Problem
Conventional locking retractors are susceptible to moisture and particulate matter ingress, which can compromise their locking operation, especially in harsh environments.
Innovation Solution
A method and apparatus for hermetically sealing locking components of retractors using an open-ended housing with sealing members to create a hermetic seal between the spool shaft and the housing, and between the locking components and the housing, ensuring that the locking components remain functional even in harsh conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If locking components are exposed to the environment for operational access, then ease of operation is improved, but reliability deteriorates due to moisture and particulate matter ingress
Solution Approach 1:
The housing is divided into a sealed interior chamber containing locking components and an exterior portion that interfaces with the environment. The spool shaft penetrates the housing wall, creating a controlled interface that separates the sealed interior from the external environment while maintaining operational access.
Solution Approach 2:
A sealing member (seal) is introduced as an intermediary element between the spool shaft and the housing wall. This seal creates a hermetic barrier that prevents moisture and particulate matter ingress while allowing the spool shaft to rotate freely for operational access to the locking components.
2Reliability
If locking components are sealed hermetically, then reliability is improved by preventing moisture and particulate matter ingress, but device complexity increases due to additional sealing structures
Solution Approach 1:
A flexible sealing member (seal) is used to create the hermetic barrier. The seal is a thin, flexible component that can deform to accommodate the rotating spool shaft while maintaining a continuous hermetic seal, thereby preventing ingress of moisture and particulate matter without requiring complex rigid sealing structures.
Solution Approach 2:
The sealing function is extracted as a separate, dedicated component (the sealing member) rather than being integrated into the housing or spool shaft structures. This allows the seal to be optimized for its specific function of preventing ingress while keeping the overall device design relatively simple and modular.
3Reliability
If the housing is sealed after locking components are installed, then reliability is improved by preventing contamination, but ease of repair deteriorates as the housing becomes hermetically sealed
Solution Approach 1:
The housing is designed as a sealed chamber that contains the locking components. The spool shaft serves as a penetration point that maintains the hermetic seal while providing a defined interface for operational access. This segmentation allows the housing to be sealed for reliability while maintaining controlled access points for operation.
Solution Approach 2:
The sealing member positioned at the spool shaft interface acts as an intermediary that maintains the hermetic seal during normal operation. The spool shaft itself serves as the access pathway, allowing operational interaction with the locking components while the seal prevents contamination ingress, thus maintaining both reliability and ease of operation.
Data Source
AI summary
A locking retractor includes a frame, a spool shaft rotatably mounted thereto, an outer surface of a base of a housing mounted to the frame with one end of the spool shaft extending into an opening defined through the base, one or more locking components arranged on an inner surface of the housing and configured to cooperate with the spool shaft to selectively block rotation of the spool relative to the frame, a sealing member configured to extend about and engage a periphery of the first opening and to extend about and engage a periphery of the spool shaft to form a seal between the base of the housing and the spool shaft to block ingress of moisture and particles, and a cover hermetically attached to the housing with the locking components sealed between the cover and the base of the housing.