Actuator Stop with Variable Radius Cutout for Rod Diameter Adaptation

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Solution Overview

Problem

Agricultural machinery actuators often experience unreliable mechanical stops due to mismatched rod diameters, leading to potential disengagement and damage during operation, as existing stop systems are not adaptable to different rod sizes.

Innovation Solution

The mechanical stop features a cutout with a succession of surfaces of different circular sections, with one radius corresponding to half the diameter of the actuator rod, ensuring reliable assembly and contact across various rod diameters, reducing the risk of disengagement by providing multiple surface contacts around the rod.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a mechanical stop with a cutout is used to limit actuator stroke, then the stop can be adjusted to different positions, but the stop becomes unreliable when the rod diameter does not exactly match the cutout diameter

Engineering Contradiction:
Improveadjustability of stop positionVSAvoidreliability of stop engagement
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The cutout is designed with a succession of surfaces having different radii instead of a single fixed radius. This allows the cutout to adapt to different rod diameters by contacting the rod at different radial positions, maintaining reliable engagement while preserving adjustability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The cutout surface is segmented into multiple surfaces with different radii. Each surface can engage with the rod at a different radial position, providing multiple contact points that ensure reliable stopping regardless of the exact rod diameter.

Inventive Principle:
Principle #1Segmentation

2Reliability

If the cutout radius is made to exactly match the rod radius for reliable contact, then the same stop cannot be used with actuators having different rod diameters

Engineering Contradiction:
Improvereliability of stop engagementVSAvoidcompatibility with different rod diameters
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The cutout is designed to perform multiple functions by incorporating surfaces with different radii. A single cutout can engage with rods of different diameters, making the stop universal and compatible with various actuator types without requiring multiple specialized stops.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The cutout geometry includes multiple surfaces with varying radii, allowing it to adapt to different rod diameter parameters. This enables the same stop design to work reliably across a range of rod sizes by selecting the appropriate contact surface.

Inventive Principle:
Principle #35Parameter changes

3Device complexity

If only line contact between the cutout and rod is provided, then the assembly is simple, but the risk of disengagement during machine operation is high

Engineering Contradiction:
Improvesimplicity of cutout designVSAvoidrisk of disengagement
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The contact between the cutout and rod is transitioned from one-dimensional line contact to two-dimensional surface contact. The succession of surfaces with different radii creates extended contact areas, increasing the contact dimension and significantly reducing the risk of disengagement.

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

Solution Approach 2:

The cutout surfaces are designed with different radii to create surface contact rather than line contact. This geometric parameter change increases the contact area between the stop and rod, providing more reliable engagement while maintaining design simplicity.

Inventive Principle:
Principle #35Parameter changes

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

This solution allows for a single stop to be compatible with multiple rod diameters, ensuring stable and reliable positioning of actuators, reducing the risk of disengagement and maintaining precise control over tool depth and adjustment.

Implementation Method 1

two movable parts connected by an elastic member

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2722529B8Device for limiting the stroke of an actuator, actuator and agricultural machine having such a device
Publication Date: 2016.06.01 KUHN SA

AI summary

The present invention relates to a stop (1) for an actuator (5) comprising two movable parts (2, 3) connected by an elastic element (4) adapted to be mounted on a rod (10) to limit the stroke of the actuator (5), each movable part (2, 3) having a cutout (6) shaped to the form of the rod (10). The stop is remarkable in that the cutout (6) of one of the movable parts (2, 3) has a succession of surfaces (15) with circular cross-sections of different radii (R1, Rn), and the radius of one of the surfaces (15) corresponds to half the diameter of the rod (10) of the actuator (5). The present invention also relates to an actuator comprising at least one stop limiting its stroke and to an agricultural machine equipped with one or more actuators having at least one such stop.