Pivoting Armrest Ratchet Lock for High Holding Force
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing armrest designs face challenges in achieving a lightweight construction with high holding forces while maintaining a narrow profile parallel to the pivot axis, and they often compromise on design flexibility.
Innovation Solution
The armrest features a locking device with a moveable first structure and an immovable second structure, utilizing a form-directional ratchet mechanism with coaxial face gears, where the locking device automatically transitions between locked and release positions based on the armrest's pivot angle, allowing upward pivoting in the locked position and downward pivoting only when the armrest reaches a specific upper position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If metal parts are used for the pivot axis and locking device components, then high holding forces can be absorbed, but the weight of the armrest increases
Solution Approach 1:
The locking device is divided into separate components: a first structure with a guide that moves axially, and a second structure with end teeth that remains immovable. This segmentation allows the use of lighter materials while maintaining structural integrity and high holding forces through the distributed tooth engagement mechanism.
Solution Approach 2:
Instead of using a traditional metal-on-metal locking mechanism, the patent inverts the approach by using a form-directional ratchet mechanism where the moving structure guides the engagement rather than directly bearing the full load. The immovable structure with end teeth provides the primary load-bearing function, allowing the moving structure to be lighter.
2Force
If traditional locking mechanisms are used, then high holding forces are achieved, but the armrest width in the pivot axis direction increases
Solution Approach 1:
The locking mechanism transitions from a radial engagement (traditional side-by-side teeth) to an axial engagement dimension. The first structure moves axially parallel to the pivot axis to engage or disengage the end teeth of the second structure, allowing the locking function to be achieved within a narrower radial profile.
Solution Approach 2:
The first structure with its guide is positioned within or alongside the second structure with end teeth, creating a compact nested arrangement. This nesting allows both structures to occupy minimal space in the pivot axis direction while maintaining the full locking functionality through axial movement.
3Weight of moving object
If a lightweight construction is used, then the armrest weight decreases, but the holding force capability is reduced
Solution Approach 1:
The patent employs composite construction where the first structure with the guide and the second structure with end teeth can be made from different materials optimized for their specific functions. This allows lightweight materials to be used where appropriate while maintaining high holding forces through the engineered tooth engagement mechanism.
Solution Approach 2:
The end teeth of the second structure are designed with specific curved engagement surfaces that optimize the distribution of holding forces. The form-directional geometry of the teeth and guide surfaces ensures that lightweight construction does not compromise the mechanical advantage and force transmission capability of the locking mechanism.
4Length of moving object
If a narrow profile is achieved, then the armrest width decreases, but the design flexibility is compromised
Solution Approach 1:
The first structure serves multiple functions: it guides the axial movement, provides the actuation interface for the locking mechanism, and engages with the second structure's end teeth. This multi-functionality within a compact axial-movement design allows narrow profile and design flexibility to coexist, as the same component enables both space efficiency and various locking position configurations.
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 enables a lightweight, flexible armrest with high holding forces and a compact profile, allowing for easy adjustment between locked and release positions, enhancing user convenience and design aesthetics.
Implementation Method 1
The first structure is loaded into the locked position by a restoring force, for example. The restoring force is provided by at least one spring, for example.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention relates to an armrest with a base part (11) on which an armrest (12) is pivotably mounted between a first position and a second position about a pivot axis (a) in opposite pivoting directions (u1, u2), the armrest (12 ) is lockable with a locking device (13) in at least one pivoting position and the locking device (13) comprises a movable first structure (31) and an immovable second structure (15) which can be releasably engaged with the first structure (31), wherein the first structure (31) is movable between a latched position and a release position and biased by a restoring force into the latched position.