Crimping Punch Notched Profile for Pull-Out Resistance
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Solution Overview
Problem
Conventional crimping tools require excessive force for crimping metal profile sections together, leading to high user fatigue and increased risk of injury, while offering insufficient resistance to pulling-out forces, necessitating the use of screws which complicate insulation insertion and pose safety hazards.
Innovation Solution
A crimping punch with a triangular spike featuring crimping faces having a primary rectilinear profile and a secondary profile with four notches defining three teeth, optimized with specific radius and depth configurations to enhance pulling-out resistance while maintaining crimping forces similar to those of smooth punches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a smooth punch is used for crimping metal profile sections, then the crimping force required is lower (approximately 36 DaN), but the resistance to pulling-out forces is insufficient (approximately 20 DaN)
Solution Approach 1:
The punch surface is modified locally by adding teeth to specific zones of the crimping faces. This creates areas of high friction and mechanical interlocking (toothed zones) while maintaining smooth areas for controlled deformation. The local addition of teeth increases resistance to pulling-out forces without requiring a uniform increase in overall crimping force across the entire punch surface.
Solution Approach 2:
The teeth are formed with specific curvature radii (between 1 mm and 2.5 mm) that optimize the mechanical interlocking effect. The curved geometry of the teeth allows for progressive engagement with the metal profile sections during crimping, distributing the force requirements and improving resistance to pulling-out while maintaining reasonable crimping force levels.
2Strength
If a toothed punch is used to increase resistance to pulling-out forces, then the resistance to pulling-out improves (greater than 20 DaN), but the force required for crimping increases significantly
Solution Approach 1:
Rather than making the entire punch surface toothed, only specific zones are equipped with teeth. This localized approach ensures that the teeth provide enhanced pulling-out resistance where most needed, while other zones maintain smooth surfaces that require less crimping force, thus balancing the two opposing requirements.
Solution Approach 2:
The geometry of the teeth is carefully optimized with specific parameters including curvature radii between 1 mm and 2.5 mm, and spacing between 1.5 mm and 3 mm. These parameter optimizations ensure that the teeth provide sufficient mechanical interlocking for high pulling-out resistance while minimizing the additional force required to deform the metal during crimping.
3Strength
If screws are used instead of crimping to achieve sufficient resistance to pulling-out, then the resistance to pulling-out is adequate, but the complexity of the assembly increases and safety risks arise
Solution Approach 1:
The toothed punch creates self-locking crimpings through mechanical interlocking with the metal profile sections. The teeth engage with the material and create a friction-based, form-fitted connection that resists pulling-out forces without requiring additional fastening elements like screws. The crimping structure itself provides the necessary strength through the geometry and distribution of the teeth.
4Strength
If the number of teeth on the punch is increased to improve pulling-out resistance, then the resistance to pulling-out increases, but the crimping force required increases even more
Solution Approach 1:
The punch features a selective distribution of teeth rather than a uniform high-density pattern across the entire surface. Teeth are concentrated in zones where they provide maximum mechanical interlocking benefit, while other zones remain smooth or have fewer teeth. This optimized spatial distribution achieves high pulling-out resistance with a moderate total number of teeth, balancing strength enhancement with acceptable crimping force requirements.
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 increases resistance to pulling-out forces by up to 150% while keeping the mean crimping force within 7% of smooth punch levels, allowing secure assembly of metal profile sections without screws, thus reducing user fatigue and safety risks.
Implementation Method 1
each crimping face furthermore comprising a secondary profile provided with four notches having a radius of between 1 mm and 2.5 mm
Implementation Method 2
The latter is obtained by machining the punch, removing material to form two concave notches of determined radius of concavity
Implementation Method 3
The resistance to pulling-out of the crimpings obtained with this type of punch is greater than that obtained with a punch in which the crimping faces (the edges) are straight (primary profile) and smooth (secondary profile), i.e. devoid of teeth
Data Source
AI summary
The present invention proposes a crimping punch making it possible to obtain a crimping that is resistant to pulling out. To this end, the punch (20) for a crimping tool comprises a fixing part (21) for fixing to the tool and a punching part (22) consisting of a spike (23) connected to the fixing part by two crimping faces (24) that each exhibit a rectilinear primary profile (241), each crimping face also comprising a secondary profile (242), provided with four notches (243) having a radius of between 1 mm and 2.5 mm, preferably between 1.2 mm and 2 mm, advantageously 1.5 mm.