Baler Needle Overload Protection via Shearbolt
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Solution Overview
Problem
Conventional agricultural balers face issues with safety protection devices that fail to reliably prevent needle overload and retraction, leading to potential damage during the baling process.
Innovation Solution
A baler design featuring a needle coupling device with a shearbolt and protrusion mechanism, where the shearbolt is positioned between the connection member and needle yoke, ensuring constant leverage and automatic retraction of needles, preventing overload and damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional safety protection devices (shearbolt or link) are used to break or slip when the drive system encounters high resistance, then needle overload is protected, but the device complexity increases and re-engagement becomes cumbersome
Solution Approach 1:
The patent employs a disposable link element that is designed to break under overload conditions. This link is a simple, inexpensive component that can be quickly replaced after activation, avoiding the complexity of reusable safety mechanisms while providing reliable needle overload protection.
Solution Approach 2:
The patent extracts the safety function from the main drive mechanism by using a separate, dedicated link element that connects the needle yoke to the drive rod. This isolated safety component can operate independently without affecting the overall system complexity, providing protection while maintaining simplicity.
2Reliability
If the needles are not withdrawn from the bale chamber in time, then the plunger will hit the needles causing damage, but adding complex timing mechanisms increases device complexity
Solution Approach 1:
The patent uses the disposable link to ensure the needles are withdrawn from the bale chamber before the plunger reaches them. The link breaks under the controlled conditions of needle retraction, preventing any possibility of the plunger hitting the needles while maintaining simple timing control through the mechanical action of the link itself.
3Reliability
If a shearbolt is used as safety device, then needle overload is protected, but replacing the broken shearbolt is cumbersome
Solution Approach 1:
The disposable link is designed as a simple, inexpensive component that can be quickly replaced after breaking. Its straightforward design and location make it much easier to access and replace compared to a shearbolt integrated into the main drive mechanism, significantly improving ease of repair.
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 provides improved protection against needle overload and ensures reliable retraction, reducing the risk of damage to the baler components and maintaining operation continuity.
Implementation Method 1
a shearbolt adapted to transfer a force from the connection member to said needle yoke during a movement from the rest position to the twine delivery position wherein the shearbolt is configured to break when there is an obstruction in the baling chamber
Implementation Method 2
a protrusion, formed at one of the connection member and the needle yoke, to abut against the other one of the connection member and the needle yoke for transferring a force to move a needle support arm of the needle yoke during a movement from the twine delivery position to the rest position
Data Source
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AI summary
Baler comprising a needle yoke wherein the needle yoke is driven via a needle coupling device comprising a connection member (120) pivotally mounted around a fixed pivot axis (122) for swinging around said fixed pivot axis, the swinging corresponding to the movement of the needle yoke (42), wherein the connection member (120) is formed cooperatively with said needle yoke by providing a shearbolt (201) adapted to transfer a force from the connection member to said needle yoke during a forward movement and a protrusion (205), formed at one of the connection member and the needle yoke, to abut against the other one of the connection member and the needle yoke during a backward movement of the needle yoke.