Vehicle Hitch Coupler with Offset Guide Slot Locking

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Solution Overview

Problem

Existing trailer hitch couplers lack reliable locking mechanisms for the drawbar eye, leading to operational complexity and potential misalignment during towing.

Innovation Solution

A hitch coupler design featuring a vertically movable clevis pin with a guide slot and offset portion, combined with a biasing mechanism that automatically biases the pin towards the extended position and imparts torsional force, allowing for easy operation and secure locking in either extended or retracted positions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a guide slot with offset portion is used to lock the pin in extended or retracted positions, then reliability of locking is improved, but device complexity increases

Engineering Contradiction:
Improvelocking reliabilityVSAvoidguide slot structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The guide slot incorporates an offset portion that creates asymmetric engagement zones for the guide member. This asymmetric geometry provides distinct locked positions (extended and retracted) with different engagement characteristics, ensuring reliable positioning while maintaining a relatively simple slot structure.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The guide member acts as an intermediary between the pin and the frame, translating vertical movement into locked positions through its interaction with the guide slot's offset portion. This mediator mechanism achieves reliable locking without requiring complex additional components.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If a biasing mechanism is added to automatically bias the pin towards extended position, then ease of operation is improved, but device complexity increases

Engineering Contradiction:
Improvepin operation easeVSAvoidmechanism complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The biasing mechanism is configured to automatically bias the pin towards the extended position without requiring external actuation. The mechanism serves itself by utilizing the natural biasing force to maintain the pin in the preferred extended position, improving ease of operation while adding minimal complexity.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The biasing mechanism changes the force parameter acting on the pin, creating a continuous biasing force that pushes the pin towards the extended position. This parameter change (application of biasing force) simplifies operation by eliminating the need for manual positioning while the mechanism remains relatively simple in structure.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If the pin member is made vertically movable for engaging drawbar eye, then adaptability is improved, but manufacturing precision requirements increase

Engineering Contradiction:
Improvedrawbar engagement adaptabilityVSAvoidpin alignment precision
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The pin member is designed to be vertically movable rather than fixed, allowing dynamic adjustment to accommodate variations in drawbar eye positioning. This dynamic capability provides adaptability while the guide slot and guide member constrain the movement to maintain adequate alignment precision without requiring extremely tight manufacturing tolerances.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The coupling mechanism is segmented into movable pin member and stationary frame components, allowing the pin to independently adjust vertically for adaptability while the guide structures maintain alignment precision through their geometric constraints rather than relying solely on manufacturing precision of the pin itself.

Inventive Principle:
Principle #1Segmentation

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 simple and reliable mechanism for locking the drawbar eye, reducing operational complexity and ensuring secure engagement, which enhances control over the towed vehicle and reduces wear on components.

Implementation Method 1

The biasing mechanism is adapted to bias the pin member towards the extended position, and is also adapted to impart a torsional force on the pin housing

Methodology Applied
Scientific EffectTorsional force: Torque

Implementation Method 2

A spring member is provided within the pin housing, and is adapted to bias the pin towards the extended position

Methodology Applied
Scientific EffectSpring biasing: Spring

Data Source

PatentEP2828104B1Automatic lock system for vehicle hitch assembly
Publication Date: 2017.05.17 SAF HOLLAND INC
  • EP2828104B1 patent drawingFigure 1
  • EP2828104B1 patent drawingFigure 1A~1B
  • EP2828104B1 patent drawingFigure 2

AI summary

A hitch coupler, comprising a frame is disclosed, wherein the frame includes a plurality of vertically spaced apart plates having apertures disposed there through. A vertically extending clevis pin is adapted to slide within the apertures of the vertically spaced apart plates between an extended position and a retracted position. The pin further includes a pin housing having a guide slot, wherein the guide slot has an offset portion used to lock the pin in either the extended position or the retracted position. Further, the pin houses an internal spring having a torsional bias that urges the pin to a locked position in either the extended or retracted position.