Lead Screw Nut Assembly With Independently Biased Flexible Fingers

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Solution Overview

Problem

Existing lead screw nut designs lack the ability to independently adjust the biasing of individual flexible fingers, leading to averaged adjustments across all fingers, which limits fine-tuning of friction and engagement with the lead screw.

Innovation Solution

A nut assembly with a cap member and adjustable biasing members for each flexible finger, allowing independent radial positioning and biasing of each finger, enabling precise adjustment of the engagement between the nut and lead screw.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a single biasing mechanism (band or o-ring) is used to bias all flexible fingers, then the structure is simple and easy to manufacture, but the ability to independently adjust biasing of each finger is lost, resulting in averaged adjustments only

Engineering Contradiction:
Improvesimplicity of biasing mechanismVSAvoidindependent adjustment capability of each finger
Core Design Contradiction:
Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The patent divides the single biasing mechanism into multiple independent biasing members, with each biasing member associated with a specific flexible finger. This segmentation allows each finger to be adjusted independently while maintaining structural simplicity through modular design.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an additional adjustment dimension by providing independent radial positioning capability for each biasing member. This allows adjustment not only of the overall biasing force but also of the individual finger engagement, adding a new degree of freedom to the system.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Device complexity

If a single biasing mechanism is used for all flexible fingers, then the device complexity is reduced, but the measurement precision and fine-tuning capability of friction and engagement are compromised

Engineering Contradiction:
Improvenumber of adjustment componentsVSAvoidfine-tuning precision of friction and engagement
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

By segmenting the biasing mechanism into individual biasing members for each flexible finger, the patent enables precise control of friction and engagement forces. Each biasing member can be independently adjusted to achieve the desired level of precision without significantly increasing overall device complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies different biasing forces to different flexible fingers based on local requirements. Each finger can be optimized independently for its specific function, allowing precise tuning of friction and engagement characteristics at each location rather than using a uniform approach.

Inventive Principle:
Principle #3Local quality

3Adaptability or versatility

If independent adjustment of each flexible finger is enabled, then fine-tuning of friction and engagement is improved, but the device complexity increases due to multiple adjustment members

Engineering Contradiction:
Improvefine-tuning capability of each fingerVSAvoidnumber of adjustment components
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent uses segmentation to create modular independent biasing members that can be adjusted individually. This modular approach provides fine-tuning capability for each finger while keeping the overall structure organized and manageable, preventing excessive complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The biasing members are designed to be radially movable relative to the central axis, providing dynamic adjustment capability. This allows the system to adapt to different operating conditions and wear patterns while maintaining a relatively simple structural framework.

Inventive Principle:
Principle #15Dynamics

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 precise control over the friction and engagement between the nut and lead screw, allowing for fine-tuning of the biasing force on each finger, improving the adjustment and compensation for misalignment and wear.

Implementation Method 1

The first adjustment member includes a first spring positioned radially between the first screw and the first flexible finger

Methodology Applied
Scientific EffectSpring: Spring

Implementation Method 2

The second adjustment member includes a second spring positioned radially between the second screw and the second flexible finger

Methodology Applied
Scientific EffectSpring: Spring

Implementation Method 3

The first adjustment member includes a first screw threadedly mounted to the cap member. The first screw is radially movable relative to the central axis by threading the first screw relative to the cap member

Methodology Applied
Scientific EffectScrew: Screw

Implementation Method 4

The second adjustment member includes a second screw threadedly mounted to the cap member. The second screw being radially movable relative to the central axis by threading the second screw relative to the cap member

Methodology Applied
Scientific EffectScrew: Screw

Data Source

PatentEP4012225B1Nut assembly with flexible fingers and self-aligning members and corresponding method of adjusting the same
Publication Date: 2024.06.12 PACIFIC BEARING CORP
  • EP4012225B1 patent drawingFigure 1
  • EP4012225B1 patent drawingFigure 2
  • EP4012225B1 patent drawingFigure 3

AI summary

A nut assembly for use with lead screws is provided. The nut assembly includes a nut member and an adjustment arrangement that can independently adjust the biasing of flexible fingers of the nut member.