D-Shaped Locking Shaft for Gear Train Engagement

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Solution Overview

Problem

Existing gear train locking devices require significant force to engage or disengage, especially when under load or while the gear train is moving, and often necessitate the elimination of rotational load for disengagement, which is inefficient and difficult to manage.

Innovation Solution

A gear train locking device utilizing a D-shaped locking shaft that rotates between engaged and disengaged positions through sliding contact with curved surfaces on the gear, allowing easy engagement and disengagement under load without the need for a clutch, by creating or removing physical interference with the gear train components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional locking devices are used, then the gear train can be locked, but significant force is required to engage or disengage the locking device

Engineering Contradiction:
Improvelocking capabilityVSAvoidforce required for engagement/disengagement
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The locking shaft employs a D-shaped cross-section with curved surfaces that interact with corresponding curved surfaces on the gear. This curvature allows the locking shaft to rotate smoothly between engaged and disengaged positions, reducing the force required compared to traditional flat or rigid locking mechanisms.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The locking device enables dynamic engagement and disengagement while the gear train is rotating and under load. The locking shaft can be rotated into and out of engagement positions without requiring the gear train to be stationary or the load to be removed, making the system adaptable to changing operational conditions.

Inventive Principle:
Principle #15Dynamics

2Reliability

If traditional locking devices are used, then the gear train can be locked, but the locking device requires elimination of rotational load for disengagement

Engineering Contradiction:
Improvelocking capabilityVSAvoidoperational efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The locking shaft is designed to engage and disengage dynamically while the gear train is rotating. The D-shaped cross-section allows the locking shaft to rotate into engagement with the gear's curved surfaces during rotation, and to be rotated out of engagement while the gear train continues to rotate, eliminating the need to stop the gear train for shifting operations.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The locking shaft can be pre-positioned and engaged while the gear train is already rotating and under load. The design allows engagement to occur during normal operation without requiring preliminary shutdown or load removal, maintaining continuous productivity.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If traditional locking devices are used, then the gear train can be locked, but the device complexity increases due to additional components like clutch

Engineering Contradiction:
Improvelocking capabilityVSAvoidnumber of components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent removes the clutch component from the system by designing a locking mechanism that can engage and disengage without it. The D-shaped locking shaft directly interacts with the gear's curved surfaces, eliminating the need for intermediary clutch components and simplifying the overall device architecture.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The locking shaft serves multiple functions: it locks the gear train when engaged, allows dynamic shifting during rotation, and eliminates the need for separate clutch mechanisms. This multi-functionality reduces the total number of components required in the system.

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

Data Source

PatentEP3247926B1Vertical tine tiller
Publication Date: 2019.03.27 MTD PRODUCTS INC
  • EP3247926B1 patent drawingFigure 1
  • EP3247926B1 patent drawingFigure 2
  • EP3247926B1 patent drawingFigure 3

AI summary

A gear train locking device having a locking device is provided. The gear train locking device includes a locking shaft 126 having an outside diameter 128 and a shaft axis. The locking shaft rotates about the shaft axis. Rotation of the locking shaft selectively moves the locking shaft between an engaged position and a disengaged position. The engaged position places the outside diameter of the locking shaft into engagement with at least one gear 110 to provide physical interference between the locking shaft and the gear to change the rotational motion of at least one of the gears. Another embodiment includes a locking shaft that cooperates with a plurality of gears.