Rotational Joint Constraint via Geometric Interference
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Solution Overview
Problem
Existing rotational degree of freedom joints that rely on friction for constraint face challenges with high torque requirements and potential slippage under moment and torsional loading, lacking a reliable mechanism to maintain alignment without adhesion.
Innovation Solution
A rotational degree of freedom joint constraint system that utilizes a mechanical contact or interference mechanism, incorporating a constraint feature and a locking mechanism with potting or encapsulant material to prevent relative movement between components, eliminating reliance on friction for locking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If friction-based constraint is used with low friction coefficient surfaces, then alignment adjustment is enabled, but torque value becomes very high
Solution Approach 1:
The patent replaces the friction-based mechanical constraint system with a geometric constraint system using a constraint feature (protrusion) that engages with a corresponding feature in the opening. This substitution eliminates the need for high friction coefficients and high torque values, allowing constraint with minimal force while maintaining alignment.
Solution Approach 2:
The patent changes the constraint mechanism from relying on friction coefficient parameters to relying on geometric parameters of the constraint feature (shape, size, position). This parameter change allows the joint to be constrained without requiring high torque, as the constraint is achieved through geometric interference rather than frictional forces.
2Reliability
If preload nut is used to produce normal load, then friction-based constraint is achieved, but device complexity increases
Solution Approach 1:
The patent replaces the complex preload nut and friction-based constraint mechanism with a simple geometric constraint feature (protrusion) that engages with the opening. This substitution maintains reliable joint constraint while significantly reducing device complexity, as no preload adjustment or friction management is needed.
Solution Approach 2:
The patent extracts the constraint function from the complex preload nut mechanism and implements it through a simple constraint feature (protrusion). This extraction eliminates the need for preload nuts and associated complexity while maintaining effective joint constraint through geometric interference.
Data Source
AI summary
A rotational degree of freedom joint constraint system is disclosed. The system can include joint constraint hardware, such as a first component and a second component. The first component can have a rotational interface, and a constraint feature associated with the rotational interface. The second component can have a socket operable with the rotational interface to facilitate relative movement of the first component and the second component in at least one rotational degree of freedom. The second component can form an opening configured to facilitate movement of the constraint feature therein upon the relative movement of the first component and the second component. The rotational degree of freedom joint constraint system can also include a locking mechanism operable with the constraint feature. Movement of the constraint feature within the opening can be preventable by the locking mechanism to constrain the relative movement of the first component and the second component.