Pivotable Cam Mechanism for Direction-Independent Door Closing

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Solution Overview

Problem

Existing door closers face issues with insufficient closing effect at large opening angles, requiring manual intervention and being direction-dependent, leading to complexity and confusion in installation and use.

Innovation Solution

A locking device with an eccentrically arranged cam tip that can pivot relative to the cam disk, allowing for adequate closing effect at 180° opening angles and being independent of closing direction, featuring a cam with a triangular cross-section and a pivotable design that ensures uniform contact with the spring roller, preventing dead center and enabling use on both right-hand and left-hand doors without modification.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a conventional door closer with a fixed cam disk is used, then the structure is simple, but a dead center is reached at large opening angles (180°) resulting in insufficient closing effect

Engineering Contradiction:
Improveclosing effectVSAvoidstructure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The cam is made pivotable relative to the cam disk, allowing it to dynamically adjust its position during door operation. This dynamic adjustment prevents the dead center condition at 180° opening angles while maintaining adequate closing effect throughout the door's range of motion.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The locking device is divided into functionally independent components: the fixed cam disk and the pivotable cam. This segmentation allows each component to perform its specific function optimally - the cam disk provides the base structure while the cam provides the adjustable closing action.

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If a direction-dependent locking device is used, then the structure can be simplified for one direction, but high stock levels and confusion occur when purchasing and installing for different door directions

Engineering Contradiction:
Improvedirection independenceVSAvoidstructure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The locking device is designed to function equally well for both right-hand and left-hand doors through the pivotable cam mechanism. The cam can pivot in either direction to accommodate different door configurations, making the device universal and eliminating the need for direction-specific models.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The cam is designed with asymmetric pivot capability, allowing it to adapt its configuration based on the required door direction. This asymmetric design enables a single device to handle multiple configurations that would traditionally require symmetric, direction-specific designs.

Inventive Principle:
Principle #4Asymmetry

3Reliability

If the cam tip is arranged eccentrically to avoid dead center at 180°, then adequate closing effect is achieved, but the cam must be pivotable which increases complexity

Engineering Contradiction:
Improveclosing effect at large opening anglesVSAvoidcam mechanism
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The cam transitions from a fixed position to a pivotable configuration, allowing it to dynamically achieve the optimal eccentric arrangement during operation. This dynamic positioning ensures the cam tip is properly positioned to avoid dead center conditions while maintaining the simplicity of the overall mechanism.

Inventive Principle:
Principle #15Dynamics

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 provides a reliable, direction-independent closing effect even at large opening angles, reducing storage complexity and installation confusion, ensuring consistent performance for both types of doors with reduced risk of damage from uneven loading.

Implementation Method 1

a spring device (18) acting on a cam disk (14) by means of a roller (16) in order to provide a closing force

Methodology Applied
Scientific EffectSpring force: Spring

Implementation Method 2

when there is contact between the roller and the cam, a torque is applied to the cam and the cam is pivoted into one of the end positions

Methodology Applied
Scientific EffectTorque: Torque

Implementation Method 3

The folding movement of the cam is positively controlled by the roller of the spring means

Methodology Applied
Scientific EffectMechanical force through roller contact: Roller

Data Source

PatentEP3138985B1Closing device for closing a door wing
Publication Date: 2020.12.09 GRETSCH UNITAS GMBH BAUBESCHLAGFABRIK
  • EP3138985B1 patent drawingFigure 1
  • EP3138985B1 patent drawingFigure 2
  • EP3138985B1 patent drawingFigure 3

AI summary

A closing device (10) for closing a door, comprising a closer shaft (12, 62), a cam disk (14, 64) non-rotatably connected to the closer shaft (12, 62), and a spring device (18) acting on the cam disk (14, 64) by means of a roller (16) to provide a closing force, is designed and further developed with simple structural means to ensure a reliable and direction-independent closing process, such that the cam disk (14, 64) has a recess (22, 72) on a section (20, 70) projecting relative to the closer shaft (12, 62), on or in which a cam (24) is pivotably mounted, such that the cam (24) forms a cam tip projecting relative to the recess (22, 72) and can be pivoted into a first end position and/or a second end position by means of the roller (16).