Ball Joint Cable Routing via Segmented Passageways

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Solution Overview

Problem

Existing ball joints have limited range of motion and increased wear on cables, making them unsuitable for various applications, especially in robotic systems where precise control and reduced wear are essential.

Innovation Solution

A ball joint design featuring a ball housing with a socket and a ball pivot that includes a partially spherical ball head and a radial ball pin, with non-parallel passageways for cable routing and a limiter to prevent debris entry, allowing for three orthogonal axes of rotation and minimizing cable wear.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the cable exits at the rear of the ball with material cut away, then the cable can pass through, but the bearing surface is reduced causing increased ball wear

Engineering Contradiction:
Improvecable routingVSAvoidball wear
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The ball is divided into two distinct regions: a first region with a conformal bearing surface for socket contact, and a second non-conformal region with a transverse passageway for cable routing. This segmentation allows the cable passage function to be separated from the bearing surface, eliminating wear caused by material removal while maintaining adequate bearing area.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of routing the cable axially through the ball (one dimension), the invention creates a transverse passageway that extends in a direction transverse to the longitudinal axis of the ball. This dimensional change allows cable routing without compromising the bearing surface integrity.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Device complexity

If the ball joint is designed for limited range of motion, then the structure is simpler, but it is not suitable for applications requiring greater motion freedom

Engineering Contradiction:
ImprovestructureVSAvoidrange of motion
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The ball joint design incorporates features that serve multiple functions: the transverse passageway system handles both cable routing and debris exclusion, the conformal bearing surface provides reliable rotation support, and the overall structure accommodates various ranges of motion. This multi-functionality allows a single design to be adapted to different application requirements without sacrificing performance.

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

3Reliability

If cables are kept internal to the mechanism, then they avoid snagging and pinching, but they require complex routing paths through the ball joint

Engineering Contradiction:
Improvecable protectionVSAvoidrouting path
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The cable routing path is nested within the ball joint structure itself, with the transverse passageway providing an internal conduit that follows the curvature of the ball. The cable is contained within the ball housing, passing through the non-conformal region and exiting at a location that maintains internal protection while following a natural curved path rather than a straight line.

Inventive Principle:
Principle #7Nested doll (Nesting)

Data Source

PatentEP2463533B1A ball joint having a passageway for routing a cable therethrough
Publication Date: 2017.08.30 HARRIS CORP
  • EP2463533B1 patent drawingFigure 1
  • EP2463533B1 patent drawingFigure 2
  • EP2463533B1 patent drawingFigure 3

AI summary

A ball joint (1) is provided having a ball housing (10) that defines a socket (11), and a ball pivot (20) with a ball head (22) and ball pin (24), where the ball head (22) is disposed in the socket (11). A ball housing passageway (14) passes through the ball housing (10); a ball pin passageway (25) passes through the ball pin (24), and a ball head passageway (23) passes through the ball head (22). The ball pin passageway (25), ball head passageway (23) and ball housing passageway (14) are in communication with each other for routing a cable (2) through the ball joint (1). A limiter (50) may extend from an internal surface (12) of the socket (11) having a passageway (52) connected to the ball housing passageway (14). The limiter (50) prevents unlimited spinning of the ball head (22) within the socket (11).