Plastic Strap Crush Region for Column Stiffness
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Solution Overview
Problem
Existing plastic straps used in strapping machines have limited column stiffness, leading to issues like snagging, bunching, and misfeeds, especially as load sizes increase, and current solutions like ribbed straps increase material costs and spool size.
Innovation Solution
A plastic strap with a crush region formed between its sides, allowing for a bend that increases column stiffness by up to 1000% without adding material or increasing spool size, achieved by creating a longitudinal crease that can be folded or bent to form acute and obtuse angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the strap gauge is reduced to decrease thickness and material cost, then material cost decreases, but column stiffness is reduced leading to misfeeds and snagging
Solution Approach 1:
The patent applies curvature by forming a bend in the strap that creates a non-coplanar configuration with first and second angles. This curved structure increases column stiffness by distributing structural load along the bent path, allowing thinner strap material to achieve the required stiffness without increasing gauge or material cost.
Solution Approach 2:
The patent transitions from a flat, two-dimensional strap structure to a three-dimensional non-coplanar configuration by forming a bend with specific angles. This dimensional change adds structural complexity that increases column stiffness while maintaining thin gauge, resolving the contradiction between material thickness and stiffness.
2Strength
If longitudinal ribs are formed in the strap to increase column stiffness, then column stiffness increases, but fabrication cost and spool size increase
Solution Approach 1:
Instead of adding longitudinal ribs along the entire length of the strap, the patent applies a localized bend structure at a specific position. This localized structural modification provides the necessary column stiffness increase without the continuous material addition and fabrication complexity of ribbed straps throughout the entire strap length.
Solution Approach 2:
The patent changes the geometric parameters of the strap by forming a bend with specific angle measurements (first angle and second angle). This parameter change approach modifies the structural properties to increase stiffness without adding material or increasing spool size, avoiding the fabrication cost increases associated with ribbed strap production.
3Quantity of substance
If the strap is made thinner to reduce material cost, then material cost decreases, but the strap becomes difficult to feed through the chute and more prone to misfeeds
Solution Approach 1:
The bent configuration of the strap provides structural rigidity that maintains alignment during feeding through the chute. The curved structure prevents the thin strap from bowing or sagging excessively, ensuring smooth passage through the strapping machine components while maintaining cost-effective thin gauge material.
Solution Approach 2:
By transitioning from a flat to a non-coplanar three-dimensional structure, the strap gains structural integrity that facilitates reliable feeding through the chute. The dimensional change creates a stiffer structure that resists misalignment and snagging, improving ease of operation despite reduced material thickness.
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 strap exhibits significantly enhanced column stiffness, reducing snagging and misfeeds while maintaining a flat form and minimizing material costs, with less coil memory when dispensed from a spool, ensuring smooth operation in strapping machines.
Implementation Method 1
The crush region forms a line along which a bend may be formed in the strap to increase a column stiffness of the strap
Data Source
AI summary
A strap having increased column stiffness includes a leading edge and a trailing edge forming a length of the strap, a first outer edge and second outer edge defining a width of the strap, and a first side and a second side defining a thickness of the strap. A crush region is formed in the first or second side, between and generally parallel to the first and second outer edges. The crush region is defined by a thickness that is less than the thickness of the strap adjacent to the crush region. The crush region forms a line along which a bend may be formed in the strap. The bend increases the column stiffness of the strap at least about 67 percent over that of a comparable flat strap. The bend defines an acute angle and an obtuse angle in the strap as viewed in cross-section.