Upper Frame Joint Connection Plate for Construction Equipment
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Solution Overview
Problem
Conventional upper frames for construction equipment face issues with unstable weld quality, increased manufacturing costs, and reduced fatigue strength due to concentrated stress on weak end parts of connection members under load, especially when power is increased in new models.
Innovation Solution
A plate-shaped joint connection plate is welded between left and right side plates to improve weld quality, increase sectional area for enhanced rigidity and flexibility, and reduce unnecessary structural strength by cutting off the center part, allowing for easier manufacturing and reduced weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a cylindrical upper connection member is welded between side plates, then the side plates are joint-connected and supported, but the weld quality becomes poor due to unstable worker posture
Solution Approach 1:
The invention divides the connection structure into two parts: a lower connection member (cylindrical) and an upper connection member (plate-shaped). The lower connection member handles the welding to base plates, while the upper connection member provides the actual support between side plates. This segmentation allows each component to have optimized geometry for its specific function, improving both weldability and structural performance.
Solution Approach 2:
The lower connection member acts as an intermediary element that transfers loads between the base plates and the upper connection member. By introducing this intermediate component, the invention eliminates the need for workers to weld directly between side plates in difficult positions, thereby improving weld quality while maintaining structural integrity.
2Strength
If the thickness of side plates and upper connection member are increased to cope with increased power, then the structural strength is improved, but the manufacturing cost increases due to special order production
Solution Approach 1:
The invention enables easy adjustment of thickness parameters for side plates and connection members without changing the overall structural design. By standardizing the modular structure with adjustable thickness parameters, manufacturers can produce components using standard production processes rather than special orders, thereby reducing costs while maintaining required strength levels.
3Force
If moment is applied to both end parts of the upper connection member, then the same moment is applied to welded end parts and center base metal part, but the fatigue strength is reduced due to stress concentration at welded end parts
Solution Approach 1:
The invention applies different geometric properties to different parts of the connection structure. The lower connection member has a cylindrical cross-section optimized for welding to base plates, while the upper connection member has a plate-shaped cross-section optimized for providing moment of inertia and fatigue resistance. This local optimization ensures that each part has the appropriate properties for its specific loading conditions.
Solution Approach 2:
The connection structure uses a composite arrangement of cylindrical and plate-shaped members with different geometric properties. The cylindrical lower connection member provides good weldability and stress distribution at the base plate interface, while the plate-shaped upper connection member provides higher moment of inertia and fatigue strength. This composite structure combines the advantages of different geometries to overall improve performance.
Data Source
AI summary
An upper frame for construction equipment mounted to swing on a lower driving structure is provided, in which fixing pins for supporting a boom and a boom cylinder are coupled to left and right side plates that are welded on a base plate to face each other, and a plate-shaped joint connection plate is welded on the left and right side plates and the base plate, so as to support the left and right side plates by exhibiting the rigidity and flexibility against load being transferred to the fixing pins through a working device during working. The upper frame includes a base plate on which a driving means for swing the upper frame is mounted, left and right side plates vertically welded on the base plate to face each other and composed of inner and outer vertical plates to which a boom and a boom cylinder are rotatably fixed by fixing pins, respectively, and a joint connection plate having both sides welded on inner sides of the inner vertical plates and a lower end part welded on the base plate and supporting the left and right side plates by exhibiting rigidity and flexibility when reaction load from the boom is generated on the fixing pins due to load generated on the working device during working.