Quick-Coupling Pull Bar Joint for Faster Sheet Metal Straightening
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Solution Overview
Problem
Existing manual sheet metal straightening devices for vehicle body repair face issues with thread damage under high pulling forces and time-consuming setup due to screw connections.
Innovation Solution
A sheet metal straightening device with a reversible/removable connection system using a sliding pivot connection between the pulling tool and traction rod, eliminating the need for tools and providing two degrees of freedom for quick assembly and sturdy attachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a screw connection is used to attach the pulling tool to the traction rod, then the connection is secure and reliable, but the setup time increases and the threads can be damaged under high pulling forces
Solution Approach 1:
The connection system is divided into separate components: a cylindrical pin on one element and a corresponding receptacle with locking features on the other element. This segmentation allows for quick assembly without threading operations, eliminating the time-consuming aspect while maintaining connection reliability through the locking mechanism.
Solution Approach 2:
The cylindrical pin and receptacle are designed with pre-configured geometric features including locking protrusions and recesses that engage automatically upon insertion. This preliminary configuration of connection features eliminates the need for real-time threading or complex alignment during setup, reducing setup time while ensuring reliable connection.
2Reliability
If a screw connection is used to attach the pulling tool to the traction rod, then the connection is secure, but the threads can be damaged under high pulling forces
Solution Approach 1:
The threaded connection element is extracted and replaced with a cylindrical pin-based connection system. This removes the vulnerable threads from the connection interface, eliminating the risk of thread damage under high pulling forces while maintaining connection security through the pin-and-receptacle design with locking features.
Solution Approach 2:
Instead of using internal threads in the receptacle that can strip under load, the design inverts the connection approach by using a solid cylindrical pin that resists shear forces and a receptacle with external locking features. This inversion eliminates the weak point of internal threading while maintaining secure connection.
3Productivity
If a sliding pivot joint connection is used between the pulling tool and traction rod, then the setup time is reduced and tool attachment is quick, but the connection complexity increases
Solution Approach 1:
The connection features (cylindrical pin, receptacle with locking protrusions) are designed with simple local geometric qualities that enable quick assembly. The local quality of the cylindrical shape with minimal features provides both simplicity and functionality, achieving fast setup without excessive overall complexity.
Data Source
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AI summary
The invention relates to a sheet metal straightening device (1) comprising a bar (11) supporting a traction rod (12) mounted movably on the bar (11) and means for controlling the movement of the traction rod (12) relative to the bar (11), the traction rod (12) comprising at one of its ends first means for securing (13) to a pulling tool (2) of the sheet metal to be straightened, the pulling tool (2) comprising second means for securing (232), suitable for cooperating with said first means for securing (13) the traction rod (12), the first means for securing (13) being connected to the second means for securing (12) by a sliding pivot joint.