Push-Pull Chain Actuator with Curved Guide for Polygon Effect

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Push-pull chain actuators face issues with the polygon effect, leading to irregular chain speed, noise, wear, and reduced performance due to the sprocket's geometry, and require complex noncircular gear wheels or large, thick casings to mitigate these issues, which are costly and difficult to install.

Innovation Solution

A push-pull chain actuator design featuring a housing with a chain exit/entry opening, a sprocket engaging rollers, and a chain guide with arc-shaped and meandering paths to neutralize the polygon effect, ensuring steady chain speed and reduced noise, while allowing for a slimmer actuator construction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If a sprocket with few teeth is used to keep the actuator compact, then the actuator size is reduced, but the polygon effect becomes large and disruptive causing irregular chain speed and noise

Engineering Contradiction:

Improveactuator sizeVSAvoidchain speed regularity

Core Design Contradiction:

Volume of moving objectVSStability of the object's composition

Solution Approach 1:

The chain guide is designed with a curved path that has a specific radius of curvature. This curvature is calculated to compensate for the polygon effect caused by the sprocket teeth, ensuring that the chain moves at a more uniform speed despite the discrete tooth engagement. The curved guide path transforms the irregular polygonal motion into smoother linear motion.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The chain guide acts as an intermediary element between the sprocket and the chain. It mediates the interaction by providing a curved guiding path that modifies the force transmission and motion characteristics, reducing the direct impact of the polygon effect on chain speed variability.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Stability of the object's composition

If noncircular gear wheels are used to offset the polygon effect, then chain speed regularity is improved, but manufacturing complexity and cost increase

Engineering Contradiction:

Improvechain speed regularityVSAvoidsprocket manufacturing

Core Design Contradiction:

Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

The solution separates the functions of speed regulation and force transmission. The circular sprocket handles force transmission simply, while the chain guide handles speed regulation through its curved path. This segmentation allows both components to be manufactured using standard processes.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of modifying the sprocket shape to compensate for the polygon effect (as in noncircular gear wheels), the invention inverts the approach by keeping the sprocket simple and circular, and placing the compensation function in the chain guide's curved path.

Inventive Principle:

Principle #13The other way round (Inversion)

3Stability of the object's composition

If a chain exit guide supporting two rollers is provided to prevent chain instability, then chain stability is improved, but the actuator size increases due to the guide links

Engineering Contradiction:

Improvechain stabilityVSAvoidactuator size

Core Design Contradiction:

Stability of the object's compositionVSVolume of moving object

Solution Approach 1:

The chain guide combines multiple functions into a single component: it guides the chain through a curved path, provides stability support, and compensates for the polygon effect. This merging eliminates the need for separate stability support mechanisms that would increase actuator size.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The curved chain guide serves multiple purposes simultaneously: it acts as a guide path, a stability support, and a polygon effect compensator. This multi-functionality reduces the overall number of components needed and keeps the actuator compact.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS9476488B2Push-pull chain actuator with reduced chain vibrations

Publication Date: 2016.10.25 WINDOWMASTER

AI summary

A push-pull chain actuator (1) includes a housing with a chain exit/entry opening (4) and a sprocket (9) arranged to engage a push-pull chain (3). The sprocket (9) causes the polygon effect. The actuator includes a first chain guide part (10a) for guiding said push-pull chain (3) around the sprocket (9) and a second chain guide part (lob) for guiding said push-pull chain (3) at the correct angle between the chain exit/entry opening (4) and the sprocket (9). The second chain guide part (10b) is shaped and dimensioned to counteract the polygon effect. Alternatively, the second chain guide part (10b) can be shaped and dimensioned to reduce chain oscillations caused by the rollers (8c) engaging or disengaging the chain exit/entry opening (4) at the end of the second chain guide part (10b).