Doctor Rod Coupling with Form-Locking Quick Release

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Solution Overview

Problem

Existing couplings for connecting metering rods to drives in film presses are complex and time-consuming to detach due to contamination, leading to extended downtimes.

Innovation Solution

A connecting device with a receiving opening and a radially adjacent recess for a form-locking element that allows tool-free axial fixation and release of the rod, using a force-loaded form-locking element to secure against axial displacement and facilitate easy attachment and detachment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a conventional coupling arrangement is used to connect the metering rod to the drive, then the connection can be detached for rod replacement, but the loosening and closing process becomes complex and time-consuming due to contamination

Engineering Contradiction:
Improveease of rod attachment and detachmentVSAvoiddowntime for rod replacement
Core Design Contradiction:
Ease of operationVSLoss of time

Solution Approach 1:

The coupling device is segmented into distinct functional elements: a receiving opening for torque transmission and a separate recess for axial fixation. This segmentation allows the form-locking element to independently secure the connecting element axially while the receiving opening handles rotational torque, enabling simplified detachment by releasing just the form-locking element without complex multi-step coupling mechanisms.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The form-locking element is extracted as a separate, movable component from the main coupling structure. It can be independently actuated to release the connecting element, allowing rod replacement without manipulating the entire coupling arrangement. This extraction simplifies the detachment process to a single actionable step.

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If a form-locking element is used to axially fix the connecting element, then axial securing is achieved, but the device complexity increases due to the additional movable component

Engineering Contradiction:
Improveaxial securing of the rodVSAvoidcomplexity of the connecting device
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The form-locking element is merged with the receiving opening structure, where the recess is formed as an integral part of the connecting device body. This integration reduces the need for separate housing structures and minimizes the number of discrete components, thereby reducing overall device complexity while maintaining reliable axial securing functionality.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The form-locking element is designed to be force-loaded and movable under its own spring force or applied force, automatically engaging with the connecting element when inserted and requiring only simple actuation for release. This self-service design eliminates the need for complex actuation mechanisms, motors, or additional control systems, maintaining simplicity while ensuring reliable axial fixation.

Inventive Principle:
Principle #25Self-service

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

Enables quick and tool-free exchange of metering rods, reducing downtime and simplifying the process of connecting and disconnecting rods to drives.

Implementation Method 1

a force-loaded form-locking element of the connecting device engages in the receiving opening, whereby the connecting element can be axially fixed

Methodology Applied
Scientific EffectMechanical Force: Mechanical Force

Implementation Method 2

the form-locking element is movable relative to the connecting device, in particular relative to the receiving opening, in order to move the form-locking element out of the receiving opening

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP4416403B1Connecting unit and connecting device for connecting a drive device to a rod, and method for exchanging a doctor rod
Publication Date: 2025.09.24 VOITH PATENT GMBH
  • EP4416403B1 patent drawingFigure 1
  • EP4416403B1 patent drawingFigure 2
  • EP4416403B1 patent drawingFigure 3a~3c

AI summary

The invention relates to a connecting unit (11) for connecting a drive device to a rod (30), in particular to a doctor rod, the connecting unit (11) having a receiving opening (12) which is designed to axially receive a connecting element (31) arranged on a rod (30), in order to transmit a torque, and the connecting unit (11) having a recess (13) which is radially adjacent to the receiving opening (12) and by which a force-applied interlocking element (14) of the connecting unit (11) engages in the receiving opening (12), as a result of which the connecting element (31) can be fixed axially.