Trailer Hitch Ball Coupler With Adjustable Clamping Gap

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Solution Overview

Problem

Existing ball-clamping couplers for rear trailer hitches suffer from unadjustable dimensions due to fixed hemisphere parts, leading to loose gripping and instability under wear, especially when hitch ball sizes deviate.

Innovation Solution

A ball-clamping coupler with a movable and fixed block configuration, utilizing a single shaft system and an adjusting screw bolt to allow translational movement of the fixed block, adapting to dimensional deviations through an oblong hole assembly, ensuring a stable grip.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the movable ball-clamping block and fixed ball-clamping block are mounted on different rotation shafts, then the clamping blocks can rotate independently, but a connection gap is present between the adjacent clamping blocks resulting in unstable gripping

Engineering Contradiction:
Improverotational independence of clamping blocksVSAvoidgripping stability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent merges the rotation functions of the movable and fixed ball-clamping blocks onto a single common rotation shaft. This eliminates the connection gap between blocks while maintaining their ability to rotate together as a unified clamping mechanism, thereby improving gripping stability without sacrificing operational capability

Inventive Principle:
Principle #5Merging (Combining)

2Device complexity

If the dimensions of the movable hemisphere part and fixed hemisphere part are fixed, then the structure is simple, but the unadjustability results in gripping not tightened when hitch ball size deviates or decreases with wear

Engineering Contradiction:
Improvestructure simplicityVSAvoidgripping tightness
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent introduces an adjustable mechanism that allows the hemisphere parts to change their relative positions dynamically. The adjustment capability enables the clamping blocks to adapt to different hitch ball sizes and wear conditions, maintaining gripping tightness while preserving relatively simple structure through controlled adjustability

Inventive Principle:
Principle #15Dynamics

3Device complexity

If the fixed hemisphere part is made unadjustable, then the structure is stable and simple, but the horizontal posing of the load carrier cannot be ensured when hitch ball size varies

Engineering Contradiction:
Improvestructure simplicityVSAvoidhorizontal posing stability
Core Design Contradiction:
Device complexityVSStability of the object's composition

Solution Approach 1:

The patent provides adjustable mechanisms for both the position and orientation of the fixed hemisphere part. This allows the system to adapt to varying hitch ball dimensions while maintaining stable horizontal posing of the load carrier, achieving a balance between structural simplicity and operational stability through controlled adjustability

Inventive Principle:
Principle #15Dynamics

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 stable and adjustable grip by minimizing gaps between clamping blocks, accommodating size variations, and maintaining secure attachment despite wear and hitch ball deviations.

Implementation Method 1

the housing is provided with an adjusting screw bolt laterally mounted thereon, which is rotatable by screwing for pressing the fixed ball-clamping block

Methodology Applied
Scientific EffectScrew mechanism: Screw

Implementation Method 2

a rotating handle is rotatably mounted outside on the housing to drive the movable ball-clamping block to rotate toward the fixed ball-clamping block for gripping

Methodology Applied
Scientific EffectRotational motion:

Data Source

PatentEP4470802B1Ball-clamping coupler for rear trailer hitch
Publication Date: 2026.04.29 WODE GLOBAL (QINGDAO) OUTDOOR CO LTD
  • EP4470802B1 patent drawingFigure 1~2
  • EP4470802B1 patent drawingFigure 3
  • EP4470802B1 patent drawingFigure 4

AI summary

The present invention relates to the technical field of ball-clamping connection of rear trailer hitch, and in particular, to a ball-clamping coupler for a rear trailer hitch, in which the housing is provided with an upper shaft and a lower shaft therein, wherein both the movable ball-clamping block and the fixed ball-clamping block, at their upper ends, are put over on the upper shaft, while the fixed ball-clamping block, at its lower end, is put over on the lower shaft, and wherein the fixed ball-clamping block is provided with an elongated hole assembly with a radial length larger than the outer diameters of the upper shaft and the lower shaft; and in which the housing is provided with an adjusting screw bolt laterally mounted thereon, which is rotatable by screwing for pressing the fixed ball-clamping block. The beneficial effects are as follows: since a single shaft configuration is provided, in which both the movable ball-clamping block and the fixed ball-clamping block are mounted on the same shaft, the gap between the movable ball-clamping block and the fixed ball-clamping block is reduced and thus a closer and tighter gripping can be maintained; and by means of the arrangement that an oblong hole assembly cooperates with an adjusting screw bolt for pressing, the fixed hemisphere part can be moved back and forth translationally in parallel so as to achieve the purpose of adjusting the gripping gap and adapting to the dimensional deviation of the clamp ball, and thus to realize a stable gripping.