Worm-Drive Diaphragm Valve Clamping for Low-Force Tensioning

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Solution Overview

Problem

Existing process valves, particularly diaphragm valves, face challenges in efficiently tensioning the valve diaphragm for a tight seal, requiring significant actuating force and risking damage from excessive torque during assembly and disassembly.

Innovation Solution

A clamping assembly with a worm drive mechanism and self-locking trapezoidal threads, combined with a safety clutch and hybrid material composition, allows for easy tensioning of the valve diaphragm with reduced force requirements and prevents damage from excessive torque.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If conventional tensioning mechanisms are used, then the valve diaphragm can be tensioned, but significant actuating force is required and excessive torque may damage components

Engineering Contradiction:
Improveactuating forceVSAvoidcomponent damage risk
Core Design Contradiction:
ForceVSReliability

Solution Approach 1:

The patent replaces conventional direct mechanical tensioning with a worm drive mechanism that converts rotational motion into controlled axial movement of the clamping insert. The worm gear provides inherent self-locking and torque multiplication, reducing the actuating force required while preventing excessive torque application through the self-locking特性 of the worm drive

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the mechanical parameters by using a fine-pitch worm gear with high reduction ratio, transforming the input rotation into precise, low-force axial movement. The thread pitch and gear ratio are optimized to provide sufficient mechanical advantage for tensioning the diaphragm without requiring excessive input force

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If simple clamping mechanisms are used, then the structure remains simple, but the fatigue strength of connections deteriorates

Engineering Contradiction:
Improveclamping assembly structureVSAvoidfatigue strength
Core Design Contradiction:
Device complexityVSStrength

Solution Approach 1:

The clamping assembly is segmented into distinct functional components: the housing, worm drive mechanism, clamping insert with external thread, and clamping element. This segmentation allows each component to be optimized for its specific function while maintaining overall structural integrity and fatigue resistance

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent employs hybrid material composition in the clamping insert, combining metal alloy for the external thread (requiring high strength and fatigue resistance) with plastic for the worm gear engagement area (reducing torque requirements). This composite approach enhances fatigue strength while keeping the overall structure efficient

Inventive Principle:
Principle #40Composite materials

3Ease of operation

If accessible torque transmission is provided, then assembly and disassembly can be performed with hand tools, but the mechanism becomes more complex

Engineering Contradiction:
Improveassembly and disassemblyVSAvoidgearbox structure
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The torque transmission section of the worm shaft is extracted and made accessible from outside the clamping assembly housing. This allows hand tools to be applied directly to the worm shaft for assembly and disassembly operations, eliminating the need to disassemble the housing while keeping the internal gearbox structure relatively simple

Inventive Principle:
Principle #2Taking out (Extraction)

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 clamping assembly facilitates easy and secure diaphragm tensioning with minimal force, enhances fatigue strength, and protects against damage by interrupting torque transmission when thresholds are exceeded, ensuring reliable operation and extended component life.

Implementation Method 1

the gearbox comprises a worm shaft rotatably mounted in the housing, wherein the gearbox comprises a clamping insert rotatably mounted in the housing about an actuating axis, the worm gear teeth of which engage with the worm shaft

Methodology Applied
Scientific EffectWorm drive: Worm Drive

Implementation Method 2

A worm drive mechanism and self-locking trapezoidal threads

Methodology Applied
Scientific EffectSelf-locking mechanism:

Implementation Method 3

an external thread of the rotatable clamping insert engages with an internal thread of the housing in order to move the clamping insert axially along the actuating axis

Methodology Applied
Scientific EffectThread engagement: Screw

Implementation Method 4

a safety clutch and hybrid material composition, allows for easy tensioning of the valve diaphragm with reduced force requirements and prevents damage from excessive torque

Methodology Applied
Scientific EffectSafety clutch:

Data Source

PatentEP4660493A1Tensioning assembly and process valve
Publication Date: 2025.12.10 GEMU GEBR MULLER APP GMBH & CO KGAA
  • EP4660493A1 patent drawingFigure 1
  • EP4660493A1 patent drawingFigure 2
  • EP4660493A1 patent drawingFigure 3

AI summary

A clamping assembly (100) for a process valve (2) is proposed. This assembly comprises: a housing (102) with an interface (104a-b) for connection with a valve body (200); a gearbox (106) supported on the housing (102), wherein the gearbox (106) comprises a worm shaft (110) rotatably mounted in the housing (102), wherein the gearbox (106) comprises a clamping insert (120) rotatably mounted in the housing (102) about an actuating axis (S), the worm gear teeth (122) of which engage with the worm shaft (110), and wherein an external thread (124) of the rotatable clamping insert (120) engages with an internal thread (108) of the housing (102) in order to move the clamping insert (120) axially along the actuating axis (S) and relative to the housing (102) by rotation;and a clamping element (130) arranged on the output of the transmission (106), wherein the clamping element (130) comprises a contact surface (132) which is designed to clamp a lateral outer collar (332) of a valve diaphragm (300) of the process valve (2) between the clamping element (130) and the valve body (200).