Concrete Pump Support Leg Pivot Design for Machining Access
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Solution Overview
Problem
The existing articulation design of truck-mounted concrete pumps' support legs is inefficient due to the limited tool stroke of machining centers, requiring complex and expensive procedures to drill bearing bores, and results in inaccuracies and oversized components for force absorption.
Innovation Solution
A design with a pivot bolt of smaller diameter in its central region and a tapered shape, allowing for reduced overhang of bearing plates and additional space for processing, enabling precise machining and minimizing material usage, along with a triangular hollow contour for increased working space and rigid attachment to chords for enhanced force absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the bearing plates protrude over the boundary wall to accommodate the tool head for drilling bearing bores, then the machining process becomes feasible, but the overhang increases leading to larger component size and increased machine weight
Solution Approach 1:
The boundary wall is designed with a hollow contour that creates additional working space in the vertical dimension between the bearing plates. This allows the tool head to access the bearing plate surface for drilling without requiring excessive horizontal overhang, thereby reducing component size while maintaining manufacturability
Solution Approach 2:
The boundary wall features a localized hollow contour only in the region where tool access is needed, rather than increasing the overall component size. This concentrated modification provides the necessary working space for machining while minimizing the increase in component dimensions and weight
2Device complexity
If the tool stroke of the machining center is limited, then the device remains compact, but it becomes impossible to drill bearing bores from above or below without rotating the mast bracket
Solution Approach 1:
The hollow contour of the boundary wall creates vertical working space between the bearing plates, allowing the tool head to drill bearing bores from the side without requiring 180° rotation of the mast bracket. This eliminates the need for complex fixing devices and reduces machining inaccuracies
Solution Approach 2:
The hollow contour acts as an intermediary space that facilitates tool access to the bearing plates. This intermediate working space enables the machining process to proceed without rotating the mast bracket, simplifying the manufacturing procedure
3Manufacturing precision
If the mast bracket is rotated by 180° to enable drilling from above or below, then bearing bores can be machined, but complex and expensive fixing devices are required and inaccuracies occur due to the turning process
Solution Approach 1:
By creating vertical working space through the hollow contour of the boundary wall, the design allows drilling to be performed without rotating the mast bracket. This eliminates the need for complex fixing devices and prevents inaccuracies that would result from the turning process
Solution Approach 2:
Instead of rotating the mast bracket to enable tool access (conventional approach), the design inverts the solution by modifying the boundary wall structure to provide access space, thereby eliminating the need for rotation and associated complexity
4Loss of substance
If the hinge pin is positioned close to the support structure to minimize overhang, then material usage is reduced, but insufficient space remains for the processing device
Solution Approach 1:
The hollow contour of the boundary wall creates vertical working space between the bearing plates, allowing the hinge pin to be positioned close to the support structure (minimizing material usage) while still providing sufficient space for the processing device to access and machine the bearing bores
Data Source
Figure 1~3
AI summary
The invention relates to a truck-mounted concrete pump (10) with a vehicle-mounted support structure (14) for a concrete placing boom (16) and at least two support legs (22) articulated to the support structure (14) via a pivot point (20), wherein each pivot point (20) comprises two bearing plates (34) projecting laterally from one another in a fork-like manner beyond the edge of a boundary wall (32) of the support structure (14), formed from a solid material and each provided with a bearing bore (36), and a pivot pin (38) passing through the bearing bores (36). According to the invention, it is proposed that the boundary wall (32) facing the pivot pin (38) has a greater distance from the axis (40) of the pivot pin (38) in its central region between the bearing plates (34) than in its edge regions adjacent to the bearing plates (34).