Wedge-Shaped Heated Blade for Polyester Strap Welding
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Solution Overview
Problem
Strapping machines face low operating frequency due to load stopping time and struggle with effective welding of plastic straps, particularly polyester, which requires high temperatures that produce noxious gases, limiting the use of polyester straps of significant width and thickness.
Innovation Solution
A strapping system with a main assembly, abutment assembly, and locking and welding assembly that uses a vertically mobile strap supply and a heated wedge-shaped element to efficiently wrap and weld plastic straps along a conveyor, allowing for high-speed operation and effective welding of polyester straps at temperatures up to 300°C without producing noxious vapors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a traditional heated blade welding system is used for polyester straps, then welding temperature can reach the ideal melting point, but noxious gases are produced which violate environmental regulations
Solution Approach 1:
The patent changes the welding parameter from high temperature (400°C) to medium temperature (300°C) to avoid producing noxious gases while still achieving effective welding of polyester straps through the optimized heating blade design and pressure application
2Object-affected harmful factors
If welding temperature is reduced below 300°C to avoid noxious gases, then environmental compliance is achieved, but welding effectiveness is insufficient
Solution Approach 1:
The heating blade uses a composite structure with a heat-resistant ceramic coating on the heating element, allowing it to maintain high temperature capability while the contact surface operates at lower temperatures to prevent noxious gas formation during welding
Solution Approach 2:
The patent optimizes the combination of temperature (300°C), pressure (increased pressing force), and time (extended welding duration) to achieve effective welding without producing noxious gases
3Object-affected harmful factors
If friction welding or vibration-welding is used as alternative methods, then noxious gases are avoided, but the welding process becomes complex and costly
Solution Approach 1:
The patent extracts and eliminates the complex mechanical vibration or friction mechanisms from the welding system, retaining only the simplified heated blade method while optimizing its parameters to avoid noxious gas production
4Device complexity
If the adhesion area of the heating blade is kept small, then the welding process is simple, but the welding quality is insufficient for plastic strap edges
Solution Approach 1:
The patent transitions from a narrow single-point contact heating blade to a wider surface-area heating blade, changing the dimension of heat application from linear to areal, which improves welding quality by distributing heat more effectively across the strap edges
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 system enables high-frequency strapping of piles of cardboard boxes and improves the welding of plastic straps, particularly polyester, by maintaining high mechanical resistance and avoiding the production of noxious gases, thus effectively exploiting the mechanical properties of polyester straps.
Implementation Method 1
heat supply by a welding blade... a heated blade is introduced transversally between the two strap edges to be welded
Implementation Method 2
a pressing device is then applied which compresses the two edges against the heating blade, until they bring the surface material to a melting state
Implementation Method 3
a wedge-shaped element, which can be pushed in a first direction towards a lying plane of the strap wrapper
Data Source
Figure 1~1A
Figure 2~2A
Figure 3~3A
AI summary
A strapping system for a wrapping apparatus with a horizontal conveyor (T) is disclosed, of the type wherein a ring of plastic strap (R) is tightened around a travelling load to be wrapped (P), while the load moves along the conveyor. The strapping system comprises in particular a welding device for a plastic strap, wherein a heated blade (34, 106) is arranged for a substantially longitudinal relative movement with respect to the strap (R) and wherein at least one pressure element (103, 12a) is further provided, arranged so as to impart a pressure in a movable operating position with respect to the strap flaps and which acts downstream of the operating position of the movable heating blade (34, 106).