PCB Clinch Mechanism Using Rolling Toggle-Cutter Contact
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Solution Overview
Problem
Existing clinch mechanisms for assembling printed circuit boards suffer from excessive wear of expensive, elaborately machined parts due to sliding pins on flat surfaces, leading to high forces on electronic components during cutting and clinching, which can damage components and require frequent replacements.
Innovation Solution
A clinch mechanism with a drive shaft moving along a vertical axis, utilizing a toggle with an involute gear-shaped tooth that rolls across an involute trapezoidal slot on the cutter, eliminating sliding pins and reducing wear by using flat plate machined parts, and allowing for non-perpendicular cutter movement to minimize pulling forces on leads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sliding pins on flat surfaces are used to connect the vertical movement to the toggles and cutters, then the mechanism can achieve the cutting and clinching function, but excessive wear occurs on these parts requiring frequent replacement
Solution Approach 1:
The patent replaces the traditional sliding pin mechanism with a cam-based mechanical system. The cam profile is designed to convert vertical linear movement into the required oscillating motion of the cutter, eliminating the need for sliding pins that contact flat surfaces. This substitution reduces friction and wear significantly, as cam-follower contacts are point or line contacts rather than surface contacts.
Solution Approach 2:
The patent changes the motion parameters by using a specifically designed cam profile that controls the cutter's oscillating motion. The cam profile parameters (rise, fall, dwell periods, and motion curves) are optimized to achieve the cutting and clinching functions while minimizing contact stresses and wear on the cam and follower components.
2Ease of manufacture
If the cutter moves parallel to the bottom of the PCB during cutting, then the cutting action can be performed, but high forces are applied to the leads which can damage the electronic component
Solution Approach 1:
The patent implements dynamic motion control of the cutter through the cam mechanism. Instead of simple linear or parallel motion, the cutter follows a complex oscillating path defined by the cam profile. This dynamic motion allows the cutter to approach the lead at optimized angles and velocities, reducing the peak forces applied to the component while maintaining effective cutting action.
Solution Approach 2:
The cam profile is designed to prepare the cutter for the cutting action by gradually bringing it into position and orientation before the actual cutting occurs. The preliminary oscillating motion allows the cutter to engage the lead smoothly, minimizing sudden force spikes that could damage the electronic component.
3Device complexity
If round pins that slide on flat surfaces are used in the clinch mechanism, then the mechanism can be simple in structure, but excessive wear occurs requiring frequent replacement of these parts
Solution Approach 1:
The patent replaces the sliding pin mechanism with a cam-based system that uses rolling or point contact instead of sliding contact. The cam profile and follower arrangement eliminate the need for pins that slide on flat surfaces, significantly reducing wear while maintaining relatively simple mechanism structure. The cam can be manufactured as a single integrated component.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution significantly reduces wear and the need for costly part replacements, enhances the handling of sensitive components, and improves the cutting and clinching process by minimizing forces on leads, resulting in a more reliable and cost-effective assembly process.
Implementation Method 1
the contact portion of the toggle includes an involute gear shaped tooth and wherein the contact portion of the cutter includes an involute trapezoidal slot
Data Source
AI summary
A clinch mechanism for assembling a printed circuit board with electronic components includes a drive shaft configured to move along a vertical axis, a stationary anvil configured to remain stationary during movement of the drive shaft, a cutter having a cutting tip, and a toggle configured to rotate about a toggle rotation axis that includes an involute gear shaped tooth configured to roll across an involute trapezoidal slot of the cutter in order to impart movement on the cutter relative to the stationary anvil. Movement of the drive shaft along the linear axis is configured to move the cutter relative to the stationary anvil, and to move the cutting tip across the stationary anvil to cut an electronic lead located between the cutting tip and the stationary anvil, and to rotate the toggle about the axis.