Compliant Clocking Spring for Compact Shaft Angular Positioning
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Solution Overview
Problem
Current devices for locking rotatable shafts at desired positions are large and cumbersome, making them impractical for use in small, confined spaces where precise angular positioning is required.
Innovation Solution
A positioning spring system comprising compliant lobes that engage with detent surfaces on a rotatable shaft to resist rotation and bias the shaft into precise angular positions, allowing for flexible and compact angular positioning within confined spaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If spring-loaded slidable pins with notches are used for angular positioning, then precise angular positioning is achieved, but the device becomes large and cumbersome
Solution Approach 1:
The positioning mechanism is segmented into discrete clock positions with detent surfaces at specific angular intervals, allowing the shaft to be positioned at precise predetermined angles while maintaining a compact overall structure. The spring-loaded pin is divided into a body portion and a positioning element that can engage with individual detent surfaces.
Solution Approach 2:
The positioning pin is nested within a cavity in the rotatable shaft, with the pin fitting inside the shaft's positioning cavity. This nesting arrangement allows the positioning mechanism to be contained within the shaft structure itself, minimizing external footprint while maintaining precise angular positioning capability.
2Reliability
If multiple pieces and large mechanisms are used for locking, then reliable angular locking is achieved, but the device complexity increases
Solution Approach 1:
The positioning pin and spring are combined into a single integrated positioning mechanism where the spring is housed within the pin body. The detent surfaces are integrated directly into the rotatable shaft structure. This merging reduces the number of separate components while maintaining reliable angular locking through the spring-loaded engagement with detent surfaces.
Solution Approach 2:
The spring-loaded pin automatically engages with the detent surfaces to lock the shaft at predetermined angular positions without requiring external actuation or complex control mechanisms. The spring provides continuous force to maintain engagement, and the mechanism self-latches at each clock position through the interaction between the pin and detent surfaces.
3Stability of the object's composition
If conventional locking mechanisms are used, then stable positioning is achieved, but the device size becomes impractical for confined spaces
Solution Approach 1:
The positioning mechanism utilizes the radial dimension by engaging the spring-loaded pin with detent surfaces on the shaft circumference, rather than requiring axial extension. The pin engages with detent surfaces at different radial positions, allowing stable positioning without increasing the overall axial length of the mechanism, making it suitable for confined spaces.
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
Enables accurate and compact angular positioning of rotatable shafts in small spaces by using compliant lobes that flex and relax to engage with detent surfaces, providing multiple clocked angular positions without the need for large mechanisms.
Implementation Method 1
The compliant lobe can flex upon rotation of the rotatable shaft out of the one or more clocked angular positions
Data Source
AI summary
Described herein is a positioning spring configured to rotatably engage with a rotatable shaft. The rotatable shaft is configured to rotate relative to the positioning spring. The positioning spring comprises a first compliant lobe positioned at a first radial position. The first compliant lobe is configured to engage with one or more detent surfaces of the rotatable shaft to resist rotation of the rotatable shaft and to bias the rotatable shaft in one or more angular positions. The first compliant lobe is configured to flex upon engagement of the first compliant lobe with the rotatable shaft at a surface position out of contact with the detent surface.