Slotted Collet Clamp for Hydraulic Work Support Rigidity

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Solution Overview

Problem

Hydraulic work supports with thin, flexible sleeves suffer from low rigidity, manufacturing difficulties due to tight tolerances, temperature-induced distortions, and premature failure, leading to inaccurate readings and reduced load-holding capacity.

Innovation Solution

A clamping mechanism using a rigid collet with slots that allows for flexible inward or outward flexure, providing higher axial stiffness and resistance to wear, while maintaining secure grip on the plunger even with increased clearance, and ensuring full contact along the plunger's length.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If a thin-walled stainless steel sleeve is used to transfer hydraulic pressure, then the sleeve can close and grip the plunger at the required pressure, but the sleeve has very low rigidity in axial compression causing elastic deformation and work support deflection

Engineering Contradiction:
Improvegrip pressureVSAvoidaxial rigidity
Core Design Contradiction:
ForceVSStrength

Solution Approach 1:

The single thin-walled sleeve is segmented into multiple thick-walled cylindrical sleeves arranged circumferentially around the plunger. Each sleeve independently transfers hydraulic pressure to grip the plunger, while the distributed arrangement maintains high axial rigidity and prevents elastic deformation of the work support.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention uses multiple thick-walled stainless steel cylindrical sleeves instead of a single thin-walled sleeve. The thick-walled construction provides both the necessary grip pressure through hydraulic actuation and sufficient axial rigidity to prevent deflection, combining the benefits of both thin-walled (grip capability) and thick-walled (rigidity) designs.

Inventive Principle:
Principle #40Composite materials

2Force

If a small clearance with tight tolerances is designed between the sleeve and plunger, then the sleeve can grip the plunger effectively, but manufacturing becomes very difficult, costly, and time consuming

Engineering Contradiction:
Improvegrip forceVSAvoidclearance tolerance
Core Design Contradiction:
ForceVSManufacturing precision

Solution Approach 1:

The thick-walled sleeve design allows for a larger radial clearance between the sleeve inner diameter and plunger outer diameter while maintaining effective grip force. The increased wall thickness compensates for the larger clearance, enabling less precise manufacturing tolerances compared to thin-walled sleeves that require very small clearances.

Inventive Principle:
Principle #3Local quality

3Adaptability or versatility

If a thin-walled sleeve is used, then the sleeve can flex to close around the plunger, but the sleeve distorts under measurement causing inaccurate readings

Engineering Contradiction:
Improveflexibility to closeVSAvoidmeasurement accuracy
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The single flexible thin-walled sleeve is replaced with multiple thick-walled cylindrical sleeves arranged circumferentially. Each sleeve maintains sufficient flexibility to close around the plunger through hydraulic actuation, while the thick-walled construction and distributed arrangement prevent distortion during measurement, enabling accurate readings.

Inventive Principle:
Principle #1Segmentation

4Adaptability or versatility

If a soft stainless steel sleeve is used, then the sleeve can conform to the plunger, but the inner diameter becomes honed out causing premature failure

Engineering Contradiction:
Improveconformity to plungerVSAvoidservice life
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The soft thin-walled sleeve is replaced with multiple hard thick-walled stainless steel cylindrical sleeves. The thick-walled construction resists honing out and wear, preventing premature failure while maintaining the ability to conform to and grip the plunger through hydraulic actuation.

Inventive Principle:
Principle #40Composite materials

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 enhances the rigidity and durability of the work support, allowing for more generous manufacturing tolerances, improved accuracy, and increased load-holding capacity, while maintaining secure clamping at lower pressures.

Implementation Method 1

hydraulic pressure is applied to the outside of the sleeve to squeeze the sleeve against the plunger, thereby locking it against the work piece

Methodology Applied
Scientific EffectHydraulic pressure: Hydraulic Press

Implementation Method 2

squeeze the sleeve against the plunger, thereby locking it

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 3

high loads applied to the end of the work support plunger can result in elastic deformation to the sleeve inside the work support

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP3344410B1Clamping mechanism for hydraulic work support
Publication Date: 2021.12.15 VEKTEK INC
  • EP3344410B1 patent drawingFigure 1
  • EP3344410B1 patent drawingFigure 2
  • EP3344410B1 patent drawingFigure 3

AI summary

A work support and method of clamping a translatable component of a hydraulic work support system. The work support may include a rigid, hollow slotted collet, a sleeve, and the translatable component, such as a plunger or rod. Hydraulic fluid may be pumped into an inlet of the hydraulic work support system to hydraulically actuate the translatable component outward from a first retracted position to a second extended position. The hydraulic fluid may further be pumped to the sleeve at a sufficient pressure that the sleeve presses against the collet. The collet responds thereto by flexing into contact with the translatable component, thus holding the translatable component in the second extended position. The slots in the collet allow for flexure even when using a thicker material with stronger column strength.