Rotational Lockout Mechanism for Agricultural Control Levers

Solution Overview

Problem

Existing control lever lockout mechanisms for vehicles, such as agricultural tractors, face reliability and robustness issues due to friction and contamination, particularly in sliding lockout members which can hinder their operation.

Innovation Solution

A control lever lockout mechanism featuring a pivotally supported lockout member and a lever lockout slot, allowing for rotational action between locked and unlocked positions, enhancing reliability and robustness by reducing friction and contamination effects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a sliding lockout member is used in a control lever lockout mechanism, then the mechanism can secure control levers in a neutral position, but the sliding motion is hindered by friction and contamination reducing reliability

Engineering Contradiction:

ImprovereliabilityVSAvoidfriction and contamination

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent inverts the conventional sliding motion by implementing a rotational motion for the lockout member. Instead of the lockout member sliding linearly along the control lever, it rotates about a pivot point, with a cam surface engaging the control lever's slot. This rotational movement eliminates the sliding friction and contamination issues that plague linear sliding mechanisms, thereby improving reliability in harsh environments.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent employs curved cam surfaces on the lockout member that engage with the control lever's slot. The cam surface transitions from a first position to a second position through rotational movement, creating a smooth arc-shaped engagement path. This curvature allows for gradual engagement and disengagement of the lockout mechanism, reducing impact forces and minimizing wear from contamination, thus enhancing reliability.

Inventive Principle:

Principle #14Spheroidality (Curvature)

2Reliability

If a sliding lockout member is used in a control lever lockout mechanism, then the mechanism can prevent accidental activation, but the sliding motion is hindered by friction and contamination reducing robustness

Engineering Contradiction:

ImproverobustnessVSAvoidfriction and contamination

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent inverts the conventional sliding motion by implementing a rotational motion for the lockout member. Instead of the lockout member sliding linearly along the control lever, it rotates about a pivot point, with a cam surface engaging the control lever's slot. This rotational movement eliminates the sliding friction and contamination issues that plague linear sliding mechanisms, thereby improving reliability in harsh environments.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent employs curved cam surfaces on the lockout member that engage with the control lever's slot. The cam surface transitions from a first position to a second position through rotational movement, creating a smooth arc-shaped engagement path. This curvature allows for gradual engagement and disengagement of the lockout mechanism, reducing impact forces and minimizing wear from contamination, thus enhancing reliability.

Inventive Principle:

Principle #14Spheroidality (Curvature)

3Reliability

If a rotational lockout member is used instead of a sliding lockout member, then friction and contamination are reduced improving reliability, but the mechanism complexity increases

Engineering Contradiction:

ImprovereliabilityVSAvoidmechanism complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the locking and unlocking functions into a single rotational motion of the lockout member. The cam surface is designed such that rotation in one direction engages the lockout slot to secure the control lever, while rotation in the opposite direction disengages it. This consolidation of functions into a single moving component reduces overall mechanism complexity despite the rotational motion, while maintaining improved reliability.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The lockout member serves multiple functions through its rotational movement: it can lock the control lever in place, unlock it for adjustment, and potentially indicate the locked state through its position. The cam surface geometry inherently provides both the locking engagement and the release mechanism, eliminating the need for separate components and reducing overall system complexity while maintaining high reliability.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentEP2302482B1Control lever lockout mechanism for a vehicle

Publication Date: 2015.07.22 DEERE & CO

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AI summary

A control lever lockout mechanism (10) for a vehicle, in particular an agricultural tractor or utility vehicle, comprises a housing (12), a control lever (20) having a lower part (22) pivotally supported in the housing (12), the lower part (22) having a lever lockout slot (38) formed therein, and a lockout member (14) pivotally supported in the housing (12). The lockout member (14) is rotatable between a locked position, wherein a portion of the lockout member (14) is received by the lever lockout slot (38), and an unlocked position, wherein the portion of the lockout member (14) is removed from the lever lockout slot (38).