Flush Door Leaf Assembly With Tolerance-Compensated Rosette Mounting

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Solution Overview

Problem

Existing methods for manufacturing door leaves with flush-mounted door hardware face challenges in accommodating manufacturing tolerances, leading to functional defects and increased costs due to manual labor and potential safety hazards during milling operations.

Innovation Solution

A method involving CNC machining to create precise recesses for mortise locks and rosettes, allowing for radial adjustment and tolerance compensation using insertion sleeves and adhesive fixation, enabling automated production of door leaves with flush-mounted door hardware.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If CNC machining is used to create precise recesses for mortise locks and rosettes, then manufacturing precision is improved, but device complexity increases

Engineering Contradiction:
Improveprecision of recesses for mortise locks and rosettesVSAvoidcomplexity of CNC machining setup
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The door leaf production process is segmented into distinct CNC machining operations: first machining the lock pocket and lock follower positioning, then separately machining the rosette recess and substructure recess. This segmentation allows each operation to be optimized independently for precision while maintaining overall process manageability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces intermediate reference elements (locking pins, positioning fixtures) that mediate between the CNC machining operations and the final assembly. These intermediaries ensure precise positioning without requiring the CNC machine to directly control every aspect of the complex assembly process.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If radial adjustment capability is provided for substructure positioning, then adaptability is improved, but manufacturing time increases

Engineering Contradiction:
Improveradial adjustment capability for substructureVSAvoidtime for radial positioning and adjustment
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The substructure is pre-designed with built-in radial adjustment capability and reference features that enable quick positioning. The recess geometry and positioning elements are prepared in advance during CNC machining, so that during assembly, the substructure can be rapidly adjusted radially without time-consuming measurements or calculations.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The substructure incorporates self-positioning features that automatically guide its radial alignment with the lock follower. The design includes self-aligning mechanisms where the substructure's own geometry facilitates its correct positioning, reducing the need for external adjustment tools and manual intervention.

Inventive Principle:
Principle #25Self-service

3Productivity

If automated CNC production is implemented, then productivity is improved, but manufacturing precision may be compromised due to tolerance accumulation

Engineering Contradiction:
Improveautomated production capabilityVSAvoidprecision maintenance across multiple machining operations
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent implements a feedback mechanism where the position of the lock follower (machined first) serves as a reference for positioning subsequent features. The CNC program uses measured actual positions from previous operations to adjust subsequent machining parameters, compensating for tolerance accumulation and maintaining overall precision throughout the automated production process.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The CNC machining process dynamically adjusts parameters between operations based on actual measured positions. Instead of relying solely on fixed nominal dimensions, the system modifies machining parameters (positions, depths, orientations) for subsequent operations based on feedback from previous operations, thereby maintaining precision despite automated manufacturing tolerances.

Inventive Principle:
Principle #35Parameter changes

4Ease of manufacture

If manual labor is reduced through automation, then ease of manufacture is improved, but safety hazards may increase during machining operations

Engineering Contradiction:
Improvereduction of manual laborVSAvoidsafety hazards during milling operations
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent extracts the dangerous aspects of manual labor (direct handling of cutting tools, close proximity to spinning mill cutters) and replaces them with automated CNC machinery. The hazardous operations are performed by machines with inherent safety features, while operators work from a safe distance controlling the process, thereby reducing manual labor while maintaining or improving safety.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP4575148B1Method, device, kit of parts, arrangement and computer program for the automated production of a door leaf
Publication Date: 2026.04.08 HUGA KG
  • EP4575148B1 patent drawingFigure 1~2
  • EP4575148B1 patent drawingFigure 3~4
  • EP4575148B1 patent drawingFigure 5

AI summary

To improve the series production of high-quality door leaves with a high-quality appearance, the invention provides a method, a device, a set of parts, an arrangement, and a computer program for the automated manufacture of a door leaf with a leaf-covering door fitting. First, recesses (21, 46, 48) for receiving the lock and door fitting components are created in a door leaf body (74) made of machinable material by numerically controlled machining; then, a mortise lock (20) is mounted in a lock recess, and subsequently, a substructure and a cover rosette (32) are mounted in recesses on the broad side of the door leaf (15). The substructure is inserted with play into a substructure receiving recess with radial play, positioned therein in alignment with a position of a lock follower (44), and fixed.In some embodiments, the substructure for supporting a handle (36) has an insert sleeve (58) with a cover collar (60) which covers the radial gap on an inner diameter of the cover rosette, which is to be provided for tolerance compensation.