Telescopic Door Closer Arm for Hold Open Stress Reduction

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Solution Overview

Problem

Existing door closer arrangements with hold open devices often create obstacles when trying to pass large items through doors, as they can be overstressed and not easily overridden, leading to discomfort and potential damage.

Innovation Solution

A door closer arrangement featuring an arm with an outer and inner sliding component, a spring arrangement to maintain the inner arm's normal position, and a release device that activates when sufficient external force is applied, allowing the inner arm to extend and increase the door opening angle, reducing stress on the hold open device.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If the hold open device is overridden to open the door more, then the door opening angle increases, but the hold open device experiences extra stress and may not operate smoothly

Engineering Contradiction:
Improvedoor opening angleVSAvoidstress on hold open device
Core Design Contradiction:
Length of moving objectVSStress or pressure

Solution Approach 1:

The arm is divided into an outer arm and an inner arm that can slide relative to each other. The inner arm can extend beyond the outer arm when sufficient force is applied, allowing the door to open beyond the normal hold open angle without overloading the hold open device. This segmentation enables the system to accommodate larger door openings while maintaining normal stress levels on the hold open mechanism.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The arm transitions from a fixed rigid structure to a dynamic telescopic structure where the inner arm can slide out relative to the outer arm. This dynamic configuration allows the arm length to change based on the door opening requirements, enabling greater opening angles when needed while maintaining the original arm length for normal operations.

Inventive Principle:
Principle #15Dynamics

2Length of moving object

If the hold open device is overridden to open the door more, then the door opening angle increases, but the operation becomes less smooth for users

Engineering Contradiction:
Improvedoor opening angleVSAvoidsmoothness of door operation
Core Design Contradiction:
Length of moving objectVSEase of operation

Solution Approach 1:

The telescopic arm provides a smooth transition for increased door opening by allowing the inner arm to slide out gradually as force is applied, rather than creating a sudden mechanical override. The sliding mechanism ensures continuous, smooth motion that maintains user comfort while enabling larger door openings.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The inner arm acts as an intermediary element between the door and the hold open device. When the door needs to open beyond the normal angle, the inner arm extends to accommodate this movement, mediating the force and motion in a way that maintains smooth operation without directly stressing the hold open device.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Device complexity

If a straight arm is used with the hold open device, then the structure is simple, but the door creates an obstacle for passage when carrying large items

Engineering Contradiction:
Improvearm structureVSAvoiddoor opening flexibility
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The arm is segmented into telescopic sections (outer arm and inner arm) that can extend relative to each other. This segmentation allows the arm to increase in length when needed to accommodate large items passing through the door, while maintaining a compact configuration for normal operations, thus improving adaptability without excessive complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The inner arm is nested within the outer arm, allowing the inner arm to slide out when additional length is needed for larger door openings. This nesting arrangement provides a space-efficient solution that maintains simplicity while enabling the arm to adapt its length based on the door opening requirements.

Inventive Principle:
Principle #7Nested doll (Nesting)

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

This design allows for greater door opening space without excessive stress on the hold open device, enhancing usability and extending its lifespan by preventing override issues.

Implementation Method 1

The arm also comprises a spring arrangement 11 in order to hold the inner arm 8B, 9B in a normal position in the outer arm 8A, 9A

Methodology Applied
Scientific EffectElastic force: Elasticity

Data Source

PatentEP3789574B1A door closer arrangement
Publication Date: 2022.06.29 ABLOY OY
  • EP3789574B1 patent drawingFigure 1~2
  • EP3789574B1 patent drawingFigure 3~4
  • EP3789574B1 patent drawingFigure 5~7

AI summary

The invention comprises a door closer (1), a slide rail (3) and an arm (2). The arm is connected to the door closer (1) and to the slide rail (3). The slide rail is provided with a hold open device (4) in order to keep a door open. The arm (2) comprises an outer arm (8A, 9A) and an inner arm (8B, 9B). The inner is situated partly inside the outer arm in a sliding manner. The arm (2) also comprises a spring arrangement (11) in order to hold the inner arm (8B, 9B) in a normal position in the outer arm (8A, 9A), and a release device (10A, 10B). The release device is arranged to release the inner arm (8B, 9B) from its normal position when an external force being strong enough to active a release of the release device (10A, 10B) drives the inner arm (8B, 9B) out from the outer arm (8A, 9A).