Adjustable Armrest Guide Assembly for Play-Free Support
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Solution Overview
Problem
Existing armrests with elastically deformable guide tubes exhibit considerable play when loaded, making intermediate positions unstable and bothersome for users, as the deformation is perceived as movement, and this play cannot be eliminated in unlocked positions.
Innovation Solution
An armrest design featuring a guide assembly with cooperating non-deformable guide surfaces and an elastic bumper block that maintains contact between guides under load, preventing relative movement and eliminating perceived play by adjusting the guides' relative position according to the load, using an elastic bumper block and non-deformable guide surfaces formed from materials like rigid plastic or metal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If elastically deformable plastic rings are used as slide bearings to guide the guide tube, then the arm support can be adjusted to different positions, but considerable play is generated under load due to elastic deformation
Solution Approach 1:
The guide assembly is divided into two separate guides (first guide on base, second guide on arm support) with cooperating guide surfaces, replacing the single deformable ring bearing. This segmentation allows each guide to be rigid and non-deformable, eliminating play while maintaining adjustability through the movable configuration of the two guides relative to each other.
Solution Approach 2:
An elastic bumper block is introduced as an intermediary element between the first and second guides. This bumper block maintains contact between the cooperating guide surfaces under load, ensuring stable positioning without requiring the guide surfaces themselves to be deformable. The bumper block absorbs the elastic deformation needs while the guides remain rigid.
2Ease of operation
If elastically deformable rings are used as guide bearings, then the guide tube can move between positions, but the deformation is perceived by the user as play particularly in intermediate unlocked positions
Solution Approach 1:
Instead of using deformable elements to enable movement, the invention uses rigid non-deformable guide surfaces that maintain stable contact. The movability is achieved not through deformation but through the ability of the two guides to move relative to each other while maintaining surface contact, inverted from the conventional approach of using deformable bearings.
Solution Approach 2:
The elastic bumper block is pre-configured to urge the guides into contact, establishing stable positioning before load is applied. This preliminary action ensures that when the arm support is positioned at any location including intermediate positions, the guides are already in contact through the bumper block's urging force, eliminating perceived play before the user even applies load.
3Reliability
If rigid non-deformable guide surfaces are used, then play is eliminated, but the guides need additional mechanism to maintain contact under load
Solution Approach 1:
The elastic bumper block changes the mechanical parameter of the guide assembly by providing a compliant element that maintains contact force between the rigid guides. This parameter change (introducing elasticity in the bumper block while keeping guides rigid) eliminates play through the rigid guide surfaces while the bumper block's elastic properties automatically adjust to maintain contact under varying loads without adding complex control mechanisms.
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 armrest provides a stable and play-free experience by maintaining the arm support's position under load, reducing disturbance and perceived movement, and can be adjusted to suit user needs without the discomfort of intermediate position play.
Implementation Method 1
The guide assembly has an elastic bumper block which urges the first guide or the second guide in a first loading direction relative to the respective other of the guides such that it corresponds to the relative position of the first guide to the second guide at a defined load
Implementation Method 2
When there is a load in a second loading direction that is directed opposite to the first loading direction, such as when pivoting the arm support from a position in which a longitudinal center axis is approximately horizontally aligned into an approximately vertical orientation, the play is less disturbing since the arm support is damped by the elastic bumper block
Data Source
AI summary
An armrest has a base element, an arm-support element movable in a direction on the base element between a pair of end positions, a mount fixed on one of the elements and formed with a throughgoing hole extending in the direction, and a rod fixed on the other of the elements and extending along an axis with play through the hole of the mount. A pair of inelastic slide-bearing rings fixed in the hole at ends thereof loosely surrounds the rod. A respective elastic bearing block fixed in and relative to each of the rings presses the rod radially against a diametrally opposite inner-surface portion of the respective ring.