Detent Fitting With Wedge Locking for Fine Adjustment
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Solution Overview
Problem
Existing locking fittings for pivotable parts in furniture, such as backrests and headrests, face issues with large structural height, limited fine adjustment, and premature wear, making them difficult to use and space-inefficient.
Innovation Solution
A locking fitting with a wedge-shaped locking member that transmits force via wedge surfaces instead of teeth, allowing for a compact design, precise adjustment, and easy unlocking mechanism using a pressure nose and compression spring, along with a stop bolt for limited pivoting movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a ratchet mechanism with external toothing and pawl is used to lock the pivotable locking lever, then the locking function is achieved, but the overall height increases due to the release lever arrangement
Solution Approach 1:
The patent inverts the conventional ratchet mechanism by placing the toothing on the stationary tab instead of the moving locking lever. The locking member engages with this toothing and is actuated by a compression spring, eliminating the need for a separate release lever while maintaining the locking function. This inversion reduces the overall height of the assembly.
Solution Approach 2:
The patent combines the locking and releasing functions into a single locking member that is actuated by a compression spring. The locking member integrates the pawl function and can be easily actuated by the pressure nose, merging multiple components into one compact unit that reduces overall height.
2Strength
If the pawl is designed with sufficient load-bearing capacity, then the locking strength is ensured, but the tooth pitch becomes relatively large, precluding fine adjustment
Solution Approach 1:
By inverting the ratchet mechanism and placing the toothing on the stationary tab, the patent enables fine tooth pitch without compromising locking strength. The locking member engages with the fine toothing and uses wedge-shaped surfaces for force transmission, allowing both fine adjustment and strong locking.
Solution Approach 2:
The patent introduces wedge-shaped surfaces as an intermediary mechanism between the locking member and the toothing. These wedge surfaces transmit force efficiently, allowing the use of fine tooth pitch for precise adjustment while maintaining sufficient locking strength through the mechanical advantage of the wedge geometry.
3Reliability
If a wedge element with gear portion is used in the locking fitting, then the locking function is achieved, but the teeth wear out prematurely, making precise positioning difficult
Solution Approach 1:
The patent replaces the wear-prone gear teeth with a different engagement mechanism. The locking member engages with the toothing through wedge-shaped surfaces rather than interlocking teeth, eliminating the wear issue that affects positioning precision over time.
4Manufacturing precision
If the locking member is designed to engage with toothing, then the locking positions are defined, but the structural height increases
Solution Approach 1:
The patent inverts the conventional arrangement by placing the toothing on the stationary tab rather than the moving locking lever. This allows the locking member to engage with the toothing in a more compact arrangement, reducing structural height while maintaining precise detent position definition.
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 enables a cost-effective, space-saving, and precisely adjustable locking mechanism with increased detent positions, improving user comfort and reducing wear, while maintaining structural integrity.
Implementation Method 1
a compression spring (8), which supports the locking member (6) in the locking position
Implementation Method 2
a wedge-shaped blocking member (6), which is provided with teeth (7) on the one hand, which engage in the external toothing (4) of the head (3)
Implementation Method 3
the transmission of force in the locking position of the locking lever takes place via the wedge surfaces of the locking member lying against one another on the one hand and the stop edge on the other hand
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
The fitting has a detent lever (1) designed as a circular arc shaped head (3) with external teeth (4) at an end, where the teeth correspond to teeth (7) of a spring-loaded blocking unit (6). The blocking unit is pivotably fastened at a strap (2) by a common pivoting axis (5) arranged centrally in the head, and is designed as a wedge-shaped blocking unit. The blocking unit movably rests against a stop edge (9) of the strap with its side turned away from the teeth of the blocking unit.