Overrunning Coupling Assembly with Clustered Pawls

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Solution Overview

Problem

Existing overrunning coupling assemblies are complex and costly, with high overrun drag, which complicates the manufacturing process and increases the cost of the controlling mechanism.

Innovation Solution

An overrunning coupling assembly with clustered pawls and a control element that allows for controlled engagement and disengagement, reducing material usage and complexity by using a non-full circular control plate that reduces overrun drag and simplifies assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional overrunning coupling assemblies use full circular control plates and multiple scattered pawls, then the engagement control is comprehensive, but the device complexity and manufacturing cost increase

Engineering Contradiction:

Improveengagement controlVSAvoidassembly complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Multiple scattered pawls are merged into a single clustered pawl assembly that performs the same engagement control function, reducing the number of parts and simplifying assembly while maintaining comprehensive control over the overrunning coupling mechanism

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The clustered pawls are designed to perform multiple functions simultaneously - they engage with multiple cammed surfaces in sequence, providing both torque transfer and overrunning control through a single integrated mechanism rather than requiring separate components for each function

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If traditional assemblies use multiple scattered pawls and full circular control plates, then the engagement coverage is complete, but the overrun drag increases

Engineering Contradiction:

Improveengagement coverageVSAvoidoverrun drag

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The control plate is designed with selective openings that dynamically allow or restrict pawl movement based on the operational state, enabling the system to transition between engaged and overrunning states with minimal drag during freewheeling operation

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The control plate is segmented with specific openings positioned to allow clustered pawls to extend through only when needed for engagement, reducing continuous contact and drag during overrunning while maintaining complete engagement coverage when required

Inventive Principle:

Principle #1Segmentation

3Manufacturing precision

If traditional designs use multiple scattered pawls and complex control mechanisms, then the engagement control is precise, but the manufacturing cost increases

Engineering Contradiction:

Improveengagement precisionVSAvoidmanufacturing cost

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The clustered pawls are nested within a single control plate opening, with each pawl positioned to engage successive cammed surfaces, creating a compact integrated assembly that is easier to manufacture and assemble than scattered individual pawls

Inventive Principle:

Principle #7Nested doll (Nesting)

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

The solution provides a cost-effective, simplified overrunning coupling assembly with reduced overrun drag, enabling a more efficient and less complex controlling mechanism.

Implementation Method 1

A first set of biasing members are carried by the pawl-holding portions and urge the forward and reverse set of pawls outwardly from their respective pawl-holding portions

Methodology Applied

Scientific EffectElastic force: Spring

Implementation Method 2

A control element is mounted for controlled, shifting movement between the surfaces relative to the pawl-holding portions and operable to control position of the reverse set of clustered pawls

Methodology Applied

Scientific EffectMechanical movement: Mechanical Force

Implementation Method 3

the outer race having cammed surfaces that define a pocket in which coupling rollers are assembled... the rollers become locked with a camming action against the cam surfaces

Methodology Applied

Scientific EffectCamming action: Cam

Implementation Method 4

The reverse pawls prevent rotation between the members in a reverse direction about the first axis in their engaged position

Methodology Applied

Scientific EffectMechanical engagement: Friction

Data Source

PatentUS7344010B2Overrunning coupling assembly including clustered pawls and method for controlling the engagement of planar members

Publication Date: 2008.03.18 MEANS IND INC

AI summary

An overrunning coupling assembly and a method of controlling the engagement of planar first and second members are provided wherein the assembly includes clustered pawls and their respective pawl-holding portions. The planar first and second members have inside surfaces extending generally normal to a first axis. The pawls include a forward set of free-floating pawls and a reverse set of free-floating, clustered pawls. The forward and reverse sets of pawls are movable between a notch-engaging, engaged position and a disengaged position. Because of the clustering, a control element, disposed between the first and second surfaces, need not be fully circular and is controllably rotatable about the first axis between first and second angular positions relative to the first member.