Backhoe Boom Unit Shared Coupling Member Design
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Solution Overview
Problem
In two-piece booms for backhoes, the differing lateral widths of the first and second booms lead to non-uniform pivoted coupling members, which are costly due to the need for custom cast metal members to handle high stress during excavation, whereas standard booms have uniform widths and can share coupling members.
Innovation Solution
The second boom's lateral width is made narrower at the base end than the distal end, allowing it to be inserted between the side walls of the first boom, enabling rotation and sharing of the pivoted coupling member with standard booms, with a third region that narrows continuously from the first to the second region, maximizing side wall vertical widths near the border section for increased strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the lateral width of the second boom is made uniform from base end to distal end like a standard boom, then the manufacturing cost increases due to requiring custom cast metal coupling members, but the structural simplicity is maintained
Solution Approach 1:
The second boom is designed with non-uniform lateral width specifically at the base end side (second region) to be narrower than the distal end side (first region). This localized dimensional variation allows the boom to be inserted between the side walls of the first boom, enabling the use of standard pivoted coupling members without requiring custom cast metal components throughout the entire structure.
2Strength
If custom cast metal coupling members are used for the two-piece boom, then the connection strength is sufficient to handle high stress, but the manufacturing cost increases significantly
Solution Approach 1:
The pivoted coupling member at the base end of the first boom is designed to serve dual purposes: it couples the first boom to the running body and simultaneously accommodates the second boom's base end. This universal coupling design allows standard coupling members to be used in two-piece booms, eliminating the need for custom cast metal members while maintaining the strength required to handle high stress during excavation operations.
3Adaptability or versatility
If the lateral width of the first boom is increased to accommodate a uniform second boom, then the coupling member compatibility is improved, but the overall device size increases
Solution Approach 1:
Instead of increasing the lateral width of the first boom to accommodate a uniform second boom (conventional approach), the invention inverts the approach by making the second boom's base end narrower. This allows the second boom to fit between the side walls of the first boom without requiring the first boom to be widened, thereby maintaining compact dimensions while achieving coupling member compatibility.
Data Source
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AI summary
A pivoted coupling member of a two-piece boom can be shared with standard booms. The boom comprises a first boom having, on the base end side, a pivoted coupling member that is pivotably coupled to a boom support section, and a second boom in which the base end side is pivotably coupled to the distal end side of the first boom and in which an arm is pivotably coupled to the distal end side. In the boom, the lateral width of the main body portion 51 of the second boom (18B) is designed to be smaller in the second region (Y) of the base end side than the first region (X) of the distal end side, the base end side of the second region (Y) of the second boom (18B) in inserted between the left and right side walls (29) of the distal end side of the first boom (18A), and the second boom (18B) is pivotably coupled to the first boom so as to be capable of rotating about the lateral axis.