Load Clamp Connecting Rod Spherical Joint for Misaligned Loads

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Solution Overview

Problem

The existing load gripper design suffers from damage due to bending moments and torsion when the load-carrying eyelet is pulled at an angle not parallel to the bore, reducing reliability, service life, and load capacity, especially when multiple grippers are used with a rope or chain and a crane.

Innovation Solution

The connection between the connecting rod and the expansion cone is designed with a part-spherical outer surface and inner shell surface, allowing three-axis pivoting, and a radial support part is added to distribute forces evenly, preventing destructive surface pressures and bending moments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the connection between connecting rod and eyelet allows pivoting to accommodate lateral forces, then the adaptability to misaligned loads is improved, but bending moments and torsion are introduced into the connecting rod and expansion cone

Engineering Contradiction:
Improveadaptability to misaligned loadsVSAvoidstrength of connecting rod and expansion cone
Core Design Contradiction:
Adaptability or versatilityVSStrength

Solution Approach 1:

The patent applies spheroidality by designing the connection between the connecting rod and expansion cone with spherical bearing surfaces. The connecting rod has a spherical outer surface that fits into a spherical bearing in the expansion cone, allowing the connecting rod to pivot freely in any direction without creating bending moments or torsion. This spherical joint design enables the system to adapt to misaligned loads while protecting the structural integrity of the connecting rod and expansion cone.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Device complexity

If the connection between connecting rod and expansion cone is rigid, then the structural simplicity is improved, but damage occurs when lateral forces are applied to the eyelet

Engineering Contradiction:
Improvestructural simplicityVSAvoidreliability under lateral loading
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent replaces the rigid connection with a spherical joint connection. The connecting rod features a spherical outer surface that engages with a spherical bearing in the expansion cone, enabling the connecting rod to pivot freely in any direction. This curved surface connection allows the structure to accommodate misaligned loads without creating damaging bending moments or torsion, thereby improving reliability while maintaining relatively simple construction.

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Force

If the expansion wedges are pressed radially outward to secure the load, then the gripping force is improved, but the connecting rod and expansion cone are subjected to twisting forces when loads are misaligned

Engineering Contradiction:
Improvegripping forceVSAvoidtwisting forces on connecting rod and expansion cone
Core Design Contradiction:
ForceVSObject-affected harmful factors

Solution Approach 1:

The patent employs a spherical joint connection between the connecting rod and expansion cone, where the connecting rod has a spherical outer surface that fits into a spherical bearing. This spherical connection allows the connecting rod to pivot freely in any direction, decoupling the radial expansion force from the axial alignment. As a result, the expansion wedges can be pressed radially outward to secure the load without transmitting twisting forces to the connecting rod and expansion cone, eliminating the harmful torsional effects.

Inventive Principle:
Principle #14Spheroidality (Curvature)

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

This design ensures that no damage occurs even when forces are applied laterally, enhancing the gripper's reliability, service life, and load capacity by eliminating bending moments and torsion, and allowing for secure gripping and lifting without surface pressure issues.

Implementation Method 1

The tensile anchoring of the connecting rod (9) at both ends is designed in such a way that a partial spherical outer surface (10, 11) which is rigidly connected to the connecting rod (9) abuts against a partial spherical shell surface with the same spherical radius, so that the connecting rod (9) can be pivoted about three axes

Methodology Applied
Scientific EffectSpherical pivot mechanism: Gimbal

Implementation Method 2

The radially outer surfaces of the expanding wedges (3) are designed as toothed sub-surfaces of a circular cylinder jacket surface. When the expanding cone (4) is displaced parallel to its axis relative to the expanding wedges (3) in the direction in which its smaller end face is at the front, the expanding wedges (3) are pushed radially away from the axis of the expanding cone (4) by the lateral surface of the expanding cone (4)

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 3

The relative movement of the expansion cone (4) with respect to the expansion wedges (3) towards the opening of the bore (6) in the load (2) causes the expansion wedges (3) to be pressed radially away from the axis (5) of the expanding cone (4) and thus jam with the wall of the bore (6)

Methodology Applied
Scientific EffectWedge mechanism: Wedge

Data Source

PatentEP3192765B1Load clamp for engagement in a hole in the load
Publication Date: 2018.08.22 SIHGA GMBH
  • EP3192765B1 patent drawingFigure 1

AI summary

The invention relates to a load gripper (1) for engaging a bore (6) in a load (2), wherein several expanding wedges (3) are arranged around an expanding cone (4), which can be displaced radially outwards by axial relative displacement of the expanding cone (4) with respect to the axis (5) of the expanding cone (4) and can thereby be clamped to the outer surface of the bore (6), wherein the expanding cone (4) is tensilely connected to a load-bearing eye (8) via a connecting rod (9). Both end regions (10, 11) of the connecting rod (9) are semi-spherical and bear against semi-spherical shell surfaces with the same sphere radius on the part where they transmit force in the case of a load.