Fastener Locking Collar and Arm for Vibration-Resistant Retention
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional fastener locking mechanisms, such as split pins and safety wire, are inadequate for locking rotatable fastener components to structures, especially in large, highly loaded applications, as they require complex installation and are impractical for certain fastener arrangements.
Innovation Solution
A locking apparatus comprising a collar and a rigid arm, where the collar engages with the fastener to prevent rotation, and the arm engages with a structure to prevent rotation relative to the structure, utilizing finite order rotational symmetry and mechanical interlocks to secure the fastener in place.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If split pins are used to lock fastener components, then two relatively rotatable parts of a fastener can be locked together, but a hole must be created through the fastener components after installation which is difficult or impossible for many fastener arrangements
Solution Approach 1:
The collar is designed with a preliminary locking feature that engages with the fastener component before final tightening. The locking arm is pre-configured to engage with the collar at specific rotational positions, eliminating the need for post-installation hole creation and enabling locking to be achieved through the normal installation sequence.
Solution Approach 2:
The locking mechanism is divided into separate functional components: a collar that interfaces with the fastener component, a locking arm that provides the locking action, and engagement features that connect these elements. This segmentation allows each component to be optimized independently and simplifies installation compared to monolithic solutions like split pins.
2Adaptability or versatility
If safety wire is used to lock fasteners, then it can be used in more situations compared to split pins, but it is impractical for very large, highly loaded fasteners and requires considerable skill for correct installation
Solution Approach 1:
The locking mechanism features self-aligning engagement surfaces on the collar and locking arm that automatically position themselves during installation. The discrete rotational positions are inherently defined by the mechanical interlocking features, eliminating the need for skilled workers to precisely position safety wire or perform complex manual alignment procedures.
3Reliability
If a locking mechanism prevents rotation of fastener components, then vibration-induced loosening is prevented, but the mechanism must accommodate the finite order of rotational symmetry of the fastener component
Solution Approach 1:
The collar is designed with an asymmetric locking interface relative to the fastener component's rotational symmetry. The locking arm engages with the collar at specific discrete rotational positions that correspond to the fastener's symmetry order, creating a unique asymmetric engagement state that prevents rotation while accommodating the underlying symmetric geometry of the fastener.
Data Source
AI summary
A locking apparatus for locking the rotational position of a fastener component which is rotatable about an axis relative to a structure. The locking apparatus includes a collar and a rigid arm. The collar is configured to engage with the fastener component such that relative rotation of the collar and the fastener component is substantially prevented. The arm has a first end configured to engage with the collar such that rotation of the collar relative to the first end is substantially prevented, and a second end configured to engage with the structure such that rotation of the arm relative to the structure is substantially prevented. The collar has an inner surface having a first finite order of rotational symmetry about the axis, and an outer surface having a second, larger, finite order of rotational symmetry about the axis.