Curved X-Link Extendable Arm for Balanced Arc Motion
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Solution Overview
Problem
Existing extendable arms that form a curved shape are either unbalanced in structure or subjected to unnatural forces due to the positioning of crossing shafts and the difference in operation between cross units and telescopic cylindrical arms.
Innovation Solution
The design features cross units with rigid members that are pivotally coupled to form an X-shape, where the coupling points at both ends of each rigid member are shifted from the central axis, allowing the extendable arm to follow a curved path without being unbalanced and subjected to unnatural forces, enabling formation of various three-dimensional shapes such as cylindrical, conical, or spherical surfaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the crossing shafts are positioned at the centers of plate members, then the structure is balanced, but the extendable arm cannot form a curved shape
Solution Approach 1:
The patent applies asymmetry by positioning the crossing shafts offset from the centers of the plate members. Specifically, the first crossing shaft is positioned offset from the center of the first plate member, and the second crossing shaft is positioned offset from the center of the second plate member. This asymmetric positioning enables the extendable arm to form a curved shape when extended, resolving the contradiction between achieving a curved shape and maintaining structural balance.
2Shape
If the crossing shafts are shifted from centers to form curved shape, then the curved shape is achieved, but the structure becomes unbalanced
Solution Approach 1:
The patent applies local quality by making the offset distances specific and controlled. The first offset distance and the second offset distance are defined as specific values that are less than half the respective plate member lengths. This localized control of offset distances allows the structure to achieve curved shape while maintaining overall structural balance through proper distribution of the asymmetry.
3Shape
If telescopic cylindrical arms are used to form arch shape, then curved shape is achieved, but unnatural forces are generated due to operation difference
Solution Approach 1:
The patent applies self-service by enabling the cross units to inherently generate the curved motion through their own pivotal coupling mechanism. The cross units with offset crossing shafts automatically produce the curved path when extended or contracted, eliminating the need for external telescopic cylindrical arms and the unnatural forces that would be generated by coordinating different mechanical operations.
4Length of moving object
If cross units are coupled in one direction for linear extension, then linear motion is achieved, but curved path cannot be followed
Solution Approach 1:
The patent applies asymmetry by positioning the crossing shafts offset from the centers of the plate members. Specifically, the first crossing shaft is positioned offset from the center of the first plate member, and the second crossing shaft is positioned offset from the center of the second plate member. This asymmetric positioning enables the extendable arm to form a curved shape when extended, resolving the contradiction between achieving a curved shape and maintaining structural balance.
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 allows the extendable arm to form a satisfactorily balanced curved shape without unnatural forces, enabling versatile applications such as desk lamps, bed structures, and article holding devices with consistent lighting or object positioning regardless of extension or contraction state.
Implementation Method 1
each of the cross units is formed by two rigid members that are pivotally coupled at a central coupling point so as to cross over each other to form an X-shape
Data Source
AI summary
An extendable arm (30) is formed by a plurality of cross units (31) arranged in one direction and pivotally coupled to each other, and each of the cross units is formed by two rigid members (31a, 31b) that are pivotally coupled at a central coupling point (c) so as to cross over each other to form an X-shape. In order for the extendable arm (30) to follow a curved-line path when being extended and contracted, each of the rigid members (31a, 31b) has such a curved shape that coupling points (d, e) at both ends of the rigid member are shifted toward one side from a longitudinal axis passing through the central coupling point (c).