Polytunnel Leg With Screw Flight And Rotatable Attachment Plate
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Solution Overview
Problem
Existing polytunnel structures lack resistance to upward loads, such as those from wind, and do not provide adequate anchorage points for securing cover retaining ropes, leading to instability and potential dislodgment of legs and support members.
Innovation Solution
A polytunnel leg design featuring a screw flight for axial load resistance, attachment formations for securing ropes, and an adjustable attachment plate to accommodate vent arrangements, ensuring both stability and ventilation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If simple steel tube legs are driven into the ground, then the structure is easy to manufacture and assemble, but the legs provide little resistance to upward loads and may be pulled out of the ground
Solution Approach 1:
The screw flight is pre-formed on the leg before installation, creating threaded engagement surfaces in advance. When the leg is driven into the ground, the screw flight immediately engages the soil to resist upward loads, eliminating the need for separate anchoring actions during installation
Solution Approach 2:
The leg combines the structural function of the steel tube with the anchoring function of the screw flight, creating a composite structure that simultaneously provides structural support and soil anchorage. This integration of multiple functions into a single component resolves the contradiction between simplicity and load resistance
2Reliability
If attachment formations are positioned close to the longitudinal axes of the legs, then good anchorage of the cover is achieved, but they impede operation of vent arrangements
Solution Approach 1:
The attachment plate is made rotatable relative to the leg, allowing the attachment formations to be dynamically repositioned. When a vent arrangement is needed, the plate can be rotated to position attachment formations away from the vent path, while still maintaining secure anchorage when the plate is in a different orientation
Solution Approach 2:
The attachment system is segmented into a rotatable plate component with multiple attachment formations. This segmentation allows independent optimization of anchorage positions and vent access paths, resolving the spatial conflict between secure cover anchorage and vent operation
3Ease of operation
If attachment formations are positioned at increased distance from the longitudinal axes of the legs, then vent arrangements can operate freely, but the anchorage of the cover is weakened
Solution Approach 1:
The attachment plate serves multiple functions: it provides anchorage points for cover retention, allows rotational adjustment for vent access, and maintains structural integrity. By concentrating multiple functions in this single component, the system achieves both good anchorage and vent operation capability
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 design effectively resists upward loads, secures the polytunnel cover, and allows for adjustable anchoring to maintain ventilation while preventing leg dislodgment and cover movement.
Implementation Method 1
the presence of the screw flight resists axially applied loads
Implementation Method 2
a screw flight is secured to the elongate member
Data Source
Figure 1~5
Figure 6~9
AI summary
A tunnel leg comprising an elongate member (18) having an anchor region (20) upon which a screw flight (22) is provided, a support region (24) to which, in use, part of a cover support member (12) of an associated tunnel can be secured, and an attachment plate (26) provided with a first attachment formation (28) and a second attachment formation (30), wherein the first and second attachment formations (28, 30) are spaced from a longitudinal axis of the elongate member (18) by different spacings.