Switchable Spherical Joint Structure for Stable Spatial Positioning

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Solution Overview

Problem

Current ball joints with three degrees of freedom fail to achieve stable spatial positioning control, particularly in dynamic applications like camera pan-tilt mechanisms, as they cannot effectively control the horizontal plane during shooting.

Innovation Solution

A two-degree-of-freedom and three-degree-of-freedom switchable ball joint structure is designed, featuring a hollow sphere with a groove, a limiting pin, and worm gear assemblies that allow the sphere to adjust its degree of freedom by inserting or retracting the pin, enabling two or three degrees of rotational freedom, along with a torsion spring assembly for dynamic balance and a dustproof pad for sealing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a three-degree-of-freedom ball joint is used, then the sphere can rotate freely in space, but stable spatial positioning control cannot be achieved

Engineering Contradiction:
Improverotational freedomVSAvoidspatial positioning control
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The ball joint structure dynamically switches between three-degree-of-freedom and two-degree-of-freedom modes through the worm gear assembly. The limiting pin can be positioned to either constrain or release the groove, allowing the system to adapt its degrees of freedom based on operational requirements, thus achieving both rotational freedom and stable positioning control

Inventive Principle:
Principle #15Dynamics

2Reliability

If a limiting pin with groove structure is added to control degrees of freedom, then stable spatial positioning is achieved, but the structure becomes more complex

Engineering Contradiction:
Improvespatial positioning controlVSAvoidjoint structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The limiting pin serves multiple functions: it acts as a positioning element, a constraint mechanism, and a switching component. The groove structure on the sphere works in conjunction with the limiting pin to provide both freedom of movement and positional control, reducing the need for separate components and simplifying the overall structure despite the added functionality

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

3Ease of operation

If a worm gear assembly is used to drive the limiting pin, then degree of freedom adjustment is enabled, but the device complexity increases

Engineering Contradiction:
Improvedegree of freedom adjustmentVSAvoidgear mechanism
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The worm gear assembly acts as an intermediary mechanism that translates rotational motion into linear motion of the limiting pin. This allows easy adjustment of the degree of freedom through simple rotation of the worm gear, while the self-locking property of the worm gear provides automatic positioning without requiring additional locking mechanisms

Inventive Principle:
Principle #24Intermediary (Mediator)

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 structure allows for stable spatial positioning control with simple and convenient adjustment, providing continuous resistance and strong locking force while ensuring centering rotation and improved dustproof sealing.

Implementation Method 1

a first worm gear assembly, which is provided in the outer shell for driving the limiting pin to make a linear reciprocating motion in the vertical direction

Methodology Applied
Scientific EffectWorm drive: Worm Drive

Implementation Method 2

a dustproof pad is sandwiched between the top ring and the spherical surface of the sphere

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3798725B1Two-degree-of-freedom and three-degree-of-freedom convertible spherical joint structure
Publication Date: 2022.11.30 UNI WAY RESOURCE CO LTD
  • EP3798725B1 patent drawingFigure 1
  • EP3798725B1 patent drawingFigure 2
  • EP3798725B1 patent drawingFigure 3~4

AI summary

The present invention discloses a two-degree-of-freedom and three-degree-of-freedom switchable ball joint structure, comprising: an outer shell with an accommodating cavity; a hollow sphere, which is located in the accommodating cavity of the outer shell and is rotatable in the accommodating cavity, wherein the lower hemispherical surface of the sphere is provided with a groove; a limiting pin, which is vertically inserted in the outer shell and located below the sphere, and the axis line of which passes through the center of the sphere; a first worm gear assembly, which is provided in the outer shell for driving the limiting pin to make a linear reciprocating motion in the vertical direction; wherein the first worm gear assembly drives the top of the limiting pin to be inserted into or exit from the groove to realize the adjustment of the degree of freedom of rotation of the sphere. The two-degree-of-freedom and three-degree-of-freedom switchable ball joint structure has the advantages of simple structure and convenient adjustment.