Multi-Start Punch and Draw Stud Coupling for Faster Knockout Setup
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Solution Overview
Problem
The existing punch systems for installing conduit runs in electrical boxes are inefficient due to the time-consuming process of attaching the knockout punch to the draw stud, which can take up to sixty seconds per hole, especially when multiple holes need to be punched.
Innovation Solution
A punch system with a multi-start thread on both the punch and the draw stud, allowing for faster attachment and self-locking mechanism without the need for a nut, reducing the number of rotations required to secure the punch onto the draw stud and enhancing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a standard single-start thread is used to attach the knockout punch to the draw stud, then the connection is secure and reliable, but the attachment process becomes time-consuming requiring many rotations
Solution Approach 1:
The patent changes the thread parameter from single-start to multi-start (specifically 3-start or 4-start threads). This increases the lead of the thread, meaning the punch advances further along the draw stud with each rotation. The multi-start thread maintains secure connection while reducing the number of rotations needed from potentially 10+ down to 3-5 rotations, directly addressing the time-loss issue.
2Length of moving object
If the draw stud length is increased to accommodate longer conduit runs, then the reach is improved, but the attachment time increases proportionally
Solution Approach 1:
The multi-start thread parameter change resolves this contradiction by decoupling attachment time from draw stud length. Whether the draw stud is 2 inches or 6 inches long, the multi-start thread maintains a consistent number of rotations (3-5) needed for secure attachment, whereas a single-start thread would require proportionally more rotations for longer studs.
3Reliability
If multiple components (punch, draw stud, nut) are used to create a secure connection, then the reliability is improved, but the device complexity increases
Solution Approach 1:
The patent extracts and eliminates the nut component from the assembly. The multi-start thread on the draw stud directly engages with the knockout punch, creating a secure connection without requiring a separate nut. This reduces component count from three (punch, draw stud, nut) to two (punch, draw stud) while maintaining connection reliability through the engineered multi-start thread geometry.
Data Source
AI summary
A punch according to some embodiments of the disclosure includes a body having a punching edge and a wall forming a passageway therethrough, the wall having a multi-start thread formed thereon, and a draw stud according to some embodiments of the disclosure includes an elongated cylinder having a multi-start thread thereon which is configured to be coupled to the multi-start thread of the punch. The number of starts provided on the punch corresponds to the number of starts provided on the draw stud. The multi-start thread on the punch is engaged with the multi-start thread on the draw stud in use. A method using same to punch a hole in sheet metal is also provided.