Detent Fitting Locking Element for Stable Furniture End Positions
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Solution Overview
Problem
The existing locking fittings for furniture components, such as headrests and armrests, face issues with maintaining a defined end position due to tensile stress from upholstery material, leading to unintended swiveling and unsightly folds when lengthening the material is not feasible.
Innovation Solution
A locking element with resilient legs and a design that encompasses a cylindrical locking bolt, allowing secure holding in an angled position while enabling easy release, and an adjustable two-part shell configuration to set the end position, which can be retrofitted without significant modifications to existing fittings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the upholstery material is lengthened to prevent tensile stress, then the locking fitting can maintain its position, but this results in considerable folds forming which lead to unsightly appearance and dirty corners
Solution Approach 1:
The patent extracts the locking function from the upholstery material system and implements it through a separate locking mechanism consisting of a locking element with resilient legs that engage with a locking pin. This separates the positioning function from the upholstery material, allowing the material to remain taut without folds while the locking mechanism independently maintains the defined end position.
Solution Approach 2:
The locking element acts as an intermediary between the upholstery material's tensile force and the locking pin. The resilient legs of the locking element mediate the interaction by providing a controlled engagement mechanism that prevents unwanted pivoting back without requiring additional upholstery material length.
2Reliability
If the spring force of the locking element is increased to prevent pivoting back, then the locking position is more secure, but the locking element becomes harder to release
Solution Approach 1:
The locking element has different local properties: the resilient legs provide sufficient holding force to prevent unwanted pivoting back, while the engagement geometry with the locking pin allows easy release. The asymmetric design of the resilient legs creates a ratchet-like effect where engagement is secure but disengagement requires minimal force in the release direction.
Solution Approach 2:
The locking element utilizes dynamic resilience in its legs, allowing it to flex and absorb forces during normal operation while maintaining secure engagement. The dynamic nature of the resilient legs enables easy release when force is applied in the release direction, as the legs can deform to allow disengagement from the locking pin.
3Manufacturing precision
If a locking element is added to prevent unwanted pivoting, then the end position is defined accurately, but the device complexity increases
Solution Approach 1:
The locking element is designed with specific geometric parameters including the angle and dimensions of its resilient legs, which are optimized to provide the necessary holding force while maintaining a compact structure. The locking pin is positioned at a specific angle relative to the pivot axis to ensure proper engagement with the locking element's resilient legs.
Solution Approach 2:
The locking element is designed as a simple, inexpensive component that can be easily manufactured and potentially replaced if needed. Its straightforward geometry and use of common materials make it a cost-effective solution that adds minimal complexity to the overall locking fitting system.
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
Prevents unwanted pivoting back of the furniture components by exceeding the tensile force of the cover fabric while allowing easy release and adjustable locking positions, maintaining functionality with minimal structural changes.
Implementation Method 1
The spring force of the leg resting on the latching pin and partially encompassing it is dimensioned such that it is greater on the one hand than the effective tensile force or resilience of the cover fabric, but on the other hand it can be swiveled back easily
Data Source
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AI summary
The fitting has a pivoting latch (2) rotatably connected with a connecting latch (1). The connecting latch and the pivoting latch are locked with each other at different angular positions by a locking gear. The locking gear is externally engaged at an end position of the pivoting latch. A locking element (3) is fastened to the connecting latch in a rotation-secured manner for locking the pivoting latch in an external engaging position of the gear. A clamp (4) includes an elastic shank (5) that partially encloses a cylindrical locking pin (7) fastened to the latch (2) in a locking position.