Pivot Fitting Cover Structure to Prevent Spring Pinching

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Solution Overview

Problem

Swivel fittings in upholstered furniture often latch prematurely due to upholstery tension, leading to instability and a risk of pinching body parts or materials, and existing solutions with external springs increase this risk.

Innovation Solution

A swivel fitting design featuring a cover that surrounds the spring, transmitting its force to a tab while preventing pinching and providing a compact, protective, and functional unit, with a spiral spring and a bolt system for secure assembly and torque management.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an external spring is arranged outside the swivel fitting to apply spring force, then the swivel fitting can be held in position against upholstery tension, but the risk of pinching body parts or materials increases

Engineering Contradiction:
Improveposition holding capabilityVSAvoidpinching risk
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The spring is nested inside the cover structure, with the cover completely enclosing the spring. This nesting arrangement maintains the spring's position-holding function while eliminating the pinching hazard by preventing contact with the spring's moving parts.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The cover acts as an intermediary element between the spring and the external environment. It transmits the spring force to the bracket through defined contact points while simultaneously serving as a protective barrier that prevents direct contact with the spring, thus mediating both the force transmission and safety functions.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If a separate cover is added to surround the spring for protection, then pinching risk is reduced, but the number of individual parts increases

Engineering Contradiction:
Improvepinching protectionVSAvoidnumber of parts
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The cover is merged with the functional elements of the swivel fitting by integrating the spring force transmission capability directly into the cover structure. The cover simultaneously provides protection, transmits force to the bracket, and maintains structural integrity, eliminating the need for separate protective housing and force transmission components.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The cover is designed as a multi-functional component that combines three essential functions: (1) protective enclosure of the spring to prevent pinching, (2) force transmission from the spring to the bracket, and (3) structural support for the swivel mechanism. This universality reduces the total part count while maintaining all necessary functions.

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

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 design effectively prevents pinching and maintains furniture stability by ensuring the swivel fitting returns to its intended position without sharp edges, reducing manufacturing complexity and cost.

Implementation Method 1

a spring (14) is provided, which applies a spring force in the direction of the initial position

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2617323B1Pivot fitting for a piece of furniture, in particular an upholstered piece of furniture
Publication Date: 2014.08.27 HETTICH FRANKE
  • EP2617323B1 patent drawingFigure 1~2
  • EP2617323B1 patent drawingFigure 3
  • EP2617323B1 patent drawingFigure 4

AI summary

The fitting has two flaps (1, 2) swingably connected with one another around a common axis and spring loaded against each other by a spring i.e. spiral spring (14) such as a flat spring. A pot-shaped cover (16) surrounds the spring, and force effect of the spring is transferred to one of the flaps (1). The cover is fixed at the flaps by a central bolt (11) that is guided along a pivotal axis. The bolt comprises a multi-edge connector (12), which is fixed with respect to the flap (1). The flap (1) comprises a fixing element (6) for fastening the connector.