Bale Wrapper Power Transfer Ring and Pre-Stretcher
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Solution Overview
Problem
Bale wrappers face challenges in achieving a balance between film tightness and puncture resistance, with high stretch ratios reducing film thickness and increasing application force, leading to potential disruptions and uneven wrapping, while excessive force can weaken the film, causing punctures and disruptions in the wrapping process.
Innovation Solution
A power-driven pre-stretcher system with a power transfer ring is used to optimize film elongation, reducing the application force and ensuring consistent film application, while maintaining compact and structural integrity of the bale wrapper, allowing for efficient film use and reduced risk of disruptions during wrapping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If the stretch ratio is increased to improve film economy and tightness, then film usage becomes more economical and air-tightness improves, but puncture and tear resistance decreases
Solution Approach 1:
The pre-stretcher unit applies preliminary stretching to the film before it contacts the bale, pre-loading the elastic energy that will later provide tightness. This preliminary action allows the film to be applied at lower forces while still achieving the desired tightness, thereby maintaining puncture resistance.
Solution Approach 2:
The system dynamically adjusts the stretch ratio as a controllable parameter. By optimizing this parameter to an appropriate level (not excessive), the invention achieves the right balance between film economy, tightness, and mechanical strength, preventing film disruption while maintaining wrapping quality.
2Force
If the application force is increased to improve film tightness, then the film applies more tightly to the bale, but the film becomes more prone to punctures and disruptions
Solution Approach 1:
The pre-stretcher unit performs the stretching action before film application, separating the stretching function from the application function. This allows the film to be stretched to the desired ratio at lower forces, then applied gently to the bale, maintaining both tightness and reliability without causing disruptions.
3Productivity
If the stretch ratio is increased to reduce film thickness and cost, then film economy improves and more bales can be wrapped per reel, but the film becomes too weak and disrupts during wrapping
Solution Approach 1:
The invention optimizes the stretch ratio parameter to an appropriate level that balances film economy with film integrity. By controlling this parameter within an optimal range rather than maximizing it, the system achieves high productivity while maintaining sufficient film strength to prevent disruptions during the wrapping process.
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 enables a more economical use of film, improved air-tightness, and increased wrapping capacity with reduced risk of film punctures, ensuring a stable and efficient wrapping process by balancing film tightness and resistance.
Implementation Method 1
Passage of the film strip through the pre-stretcher unit causes elongation of the film prior to application of the film strip as successive overlapping windings on the bale
Implementation Method 2
The pre-stretched film subsequently tightens itself onto the outer surface of the bale under the action of the elastic energy stored in the pre-stretched windings, after completion of the wrapping cycle
Data Source
Figure 1
Figure 2
Figure 3a
AI summary
A bale wrapper that applies a stretch film wrapping to an agricultural bale. The present invention also relates to an agricultural bale wrapping method. There is provided a mobile agricultural bale wrapper comprising: a bale support for supporting a bale and rotating the bale about a first axis; a rotational wrapper ring comprising a film dispenser, the film dispenser comprising a holder for a roll of stretch film to dispense the film when the rotational wrapper ring is rotated; and a film pre-stretcher unit that is configured to pre-stretch the film by an elongation amount and apply the pre-stretched film to the bale; the rotational wrapper ring providing relative rotation between the bale support and the film dispenser about a second axis that extends substantially perpendicular to the first axis so that the pre-stretched film applied to the bale forms a bale wrapping that covers a side surface and end faces of the bale, and the film pre-stretcher unit comprising a drive unit to control rotation of the film pre-stretcher unit; the mobile agricultural bale wrapper further comprising: a power transfer ring, substantially adjacent the rotational wrapper ring, to transfer power to the drive unit.