Differential Thread Clamping Sleeve for Precise Spindle Coupling

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Solution Overview

Problem

Existing clamping systems for rotary machining are inefficient in terms of quick changeover, precise positioning, and resistance to contamination, particularly due to fine threads that are prone to damage and contamination issues.

Innovation Solution

A clamping system utilizing a differential threaded sleeve with threads of different pitches and bayonet threads, along with a force transmission element and displaceable mating threads, ensures a secure and contamination-resistant connection between the workpiece holder and spindle, allowing for easy and precise coupling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a fine thread with small pitch is used to achieve precise positioning and secure connection, then the connection reliability is improved, but the thread becomes more sensitive to contamination and more easily damaged

Engineering Contradiction:
Improveconnection reliabilityVSAvoidcontamination sensitivity
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The threaded sleeve is divided into two separate threaded sections, each engaging with a different mating thread. This segmentation allows each thread to have optimal pitch characteristics - one thread can have finer pitch for precise positioning while the other has coarser pitch for contamination resistance and easier engagement.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention changes the thread pitch parameter by using two different pitches in the two threaded sections. The first threaded section has a first pitch while the second threaded section has a second pitch that differs from the first, allowing optimization of each thread for its specific function.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If a single threaded section with larger pitch is used to make threads more robust and less sensitive to contamination, then the ease of operation is improved, but the coupling torque required to achieve defined clamping force increases

Engineering Contradiction:
Improveease of attachmentVSAvoidcoupling torque
Core Design Contradiction:
Ease of operationVSForce

Solution Approach 1:

The threaded sleeve is segmented into two threaded sections with different pitches. The first threaded section can have a coarser pitch for easier engagement and lower torque requirement, while the second threaded section provides the necessary clamping force through its engagement with the workpiece holder.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

By changing the pitch parameter to have two different values in the two threaded sections, the invention optimizes the balance between ease of operation (coarser first pitch) and clamping force generation (second pitch configured for force transmission).

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If frequent changes of workpiece holders are performed to adapt to different production needs, then the adaptability is improved, but the time required for attachment and detachment increases

Engineering Contradiction:
Improveadaptability to different workpiecesVSAvoidchangeover time
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The differential threaded sleeve is designed to automatically perform the tightening action during the attachment process itself. As the workpiece holder is mounted on the spindle, the differential thread mechanism automatically generates the axial displacement needed to secure the connection, eliminating the need for separate tightening operations and reducing changeover time.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention introduces dynamic functionality to the threaded sleeve, which is not merely a static fastening component but an active mechanism that converts rotational movement into axial displacement. This dynamic behavior enables automatic tightening during attachment, facilitating quicker changes.

Inventive Principle:
Principle #15Dynamics

4Manufacturing precision

If a differential thread sleeve with two threaded sections of different pitches is used to achieve both fine positioning and robust threads, then the manufacturing precision is improved, but the device complexity increases

Engineering Contradiction:
Improvepositioning precisionVSAvoidthreaded sleeve complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The threaded sleeve is segmented into two threaded sections, each with different pitch characteristics. This segmentation allows the first section to provide fine positioning precision while the second section provides robust engagement, achieving both precision and simplicity through functional division.

Inventive Principle:
Principle #1Segmentation

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 system achieves a robust and contamination-resistant connection with reduced risk of thread damage, enabling efficient and precise coupling and decoupling, while maintaining a secure torque transmission.

Implementation Method 1

The differential thread sleeve (50) has a first threaded section (52) which is designed for engagement with a first mating thread (36) on the workpiece holder (30) and a second threaded section (54) which is designed for engagement with a second mating thread (16) on the spindle (10). The rotational movement of the differential thread sleeve (50) causes it to be displaced axially, i.e., in the direction of the principal axis, relative to both mating threads, but to different degrees.

Methodology Applied
Scientific EffectDifferential thread mechanism: Screw

Data Source

PatentEP3991893B1Clamping system with spindle and workpiece holder and method for coupling the clamping system
Publication Date: 2023.05.31 HAINBUUFU GMBH SHUPANENDE TEHINIKU
  • EP3991893B1 patent drawingFigure 1A~1B
  • EP3991893B1 patent drawingFigure 2
  • EP3991893B1 patent drawingFigure 3~4

AI summary

A clamping system comprising a spindle (10) and a workpiece holder (30) is known, particularly for the rotary machining of a workpiece held by the workpiece holder (30). The workpiece holder (30) has a receiving area (90) for receiving a workpiece. The spindle (10) is designed for mounting the workpiece holder (30), with the spindle and the workpiece holder having contact surfaces facing each other. A differential thread sleeve (50) with a first threaded section (52) and a second threaded section (54) with different thread pitches is provided for fastening the workpiece holder (30) to the spindle (10). A first mating thread (36) for the first threaded section (52) is provided on the workpiece holder (30), while a second mating thread (16) for the second threaded section (54) is provided on the spindle (10).