Reinforced Four-Link Extension Arm for Higher Load Capacity
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Solution Overview
Problem
Conventional extension arm devices face challenges in providing sufficient structural strength to support suspended objects without compromising the load capacity of gas springs or increasing the weight and size of the device.
Innovation Solution
The extension arm device incorporates a joint unit with two linking arms forming a four-linkage mechanism, featuring side and corner reinforcement structures to enhance structural strength and stiffness, allowing for increased load capacity without weight or size increments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If metal sheet channels are used to reduce weight and size, then the device weight and size are reduced, but the structural strength is insufficient to bear the suspended object weight
Solution Approach 1:
The patent applies local quality by adding reinforcement structures (ridges and protrusions) only at specific critical locations on the linking arms where stress concentration occurs, rather than uniformly thickening the entire metal sheet. This allows the maintaining of overall lightweight design while providing localized strength enhancement where needed to support the suspended object.
Solution Approach 2:
The patent creates a composite structure by combining the base metal sheet material with embedded reinforcement elements (such as plastic ribs or metal inserts) within the linking arms. This composite approach allows the structure to leverage the high strength-to-weight ratio of the base material while the reinforcement elements provide additional load-bearing capacity at critical stress points.
2Strength
If reinforcement structures are added to increase load capacity, then the structural strength is improved, but the weight and size of the device increase
Solution Approach 1:
The reinforcement structures are strategically placed only at critical stress points and load-bearing regions of the linking arms, such as near pivot joints and connection points. This localized approach ensures that the additional weight is minimized while still providing sufficient strength enhancement where the mechanical stresses are highest during operation.
Solution Approach 2:
The reinforcement is segmented into discrete features such as individual ridges, ribs, or protrusions rather than using continuous thickening. This segmentation allows the reinforcement to be distributed optimally across the linking arm structure, providing strength where needed while maintaining lightweight characteristics in non-critical areas.
3Strength
If reinforcement structures are added to increase load capacity, then the structural strength is improved, but the device size increases
Solution Approach 1:
The reinforcement structures are implemented as surface-level features such as embossed ridges, raised ribs, or localized protrusions that add minimal dimensional footprint. These features increase structural strength through geometric reinforcement rather than by significantly increasing the overall volume or external dimensions of the linking arms.
Solution Approach 2:
The reinforcement is achieved by utilizing the thickness dimension of the metal sheet through formed features such as folded flanges, bent ribs, or multi-layered configurations. This allows the reinforcement to be created within the existing planar footprint of the linking arm without increasing the device's overall length, width, or height.
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 design provides enhanced structural strength and stiffness, thereby increasing the load capacity and service life of the linking arms while maintaining the range of motion and avoiding weight and size increases.
Implementation Method 1
Each of the linking arms is pivotally connected between the first and second joint brackets such that the linking arms and the first and second joint brackets are cooperatively formed as a four-linkage mechanism
Implementation Method 2
a gas spring disposed between the upper and lower channels to permit the extension arm device to be adjusted and to retain the four-linkage mechanism in a desired height position
Implementation Method 3
Each of the side walls of at least one of the linking arms has at least one side reinforcement structure which is embossed from either one of the inner and outer wall surfaces
Data Source
AI summary
An extension arm device includes first and second joint brackets and two linking arms pivotally connected therebetween to form a four-linkage mechanism. Each linking arm includes two parallel side walls and a cover wall interconnecting the side walls. Each side wall of at least one linking arm has a side reinforcement structure which is embossed from an inner or outer wall surface and which extends in a lengthwise direction so as to enhance the structural stiffness of the side wall.