Rolling Drop-Plate Door Seal for Low-Friction Gap Closure
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Solution Overview
Problem
Existing door seals, such as the secure under-door seal described in AU 2012-101071, suffer from high friction, inefficient biasing, difficulty of adjustment, and lack of compactness, particularly when closing gaps at the base of a door, which can be exploited for unauthorized access or passage of wires or optical fibers.
Innovation Solution
A movable seal comprising a drop-plate, plunger, slider, and rollers that reduce friction by allowing lateral movement and rolling action, with adjustable plunger extension and guided motion to effectively close the gap between the door and floor, incorporating a mounting plate and additional rollers to enhance stability and reduce wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional door seal mechanism is used to close the gap at the base of a door, then the gap can be sealed, but high friction occurs and large force is required to operate the seal
Solution Approach 1:
The patent employs rollers with curved surfaces that contact the ramp surfaces, replacing traditional sliding surfaces. This curvature enables rolling motion which significantly reduces friction and the force required to move the drop-plate, while maintaining effective gap sealing
Solution Approach 2:
The rollers act as intermediary elements between the slider and the drop-plate, transferring the lateral motion of the slider into vertical motion of the drop-plate through the ramp surfaces. This intermediary mechanism reduces direct friction contact while maintaining the force transmission needed for reliable sealing
2Reliability
If a traditional door seal mechanism is used, then the gap can be closed, but wear of the moving parts occurs rapidly
Solution Approach 1:
The curved roller surfaces replace flat sliding surfaces, converting sliding friction into rolling friction. This dramatically reduces wear on the ramp surfaces and other moving parts, extending the service life of the seal components while maintaining reliable gap closure
Solution Approach 2:
The patent substitutes a sliding mechanical system with a rolling mechanical system. The rollers replace direct sliding contact between the slider and drop-plate, reducing wear through rolling motion while maintaining the mechanical advantage needed for effective sealing
3Device complexity
If a simple seal mechanism is used, then the structure remains simple, but the device lacks compactness and is difficult to adjust
Solution Approach 1:
The patent employs a threaded rod that can be rotated to adjust the plunger extension, allowing dynamic adjustment of the seal mechanism's position and travel. This provides ease of operation and adaptability while maintaining a relatively simple overall structure
Solution Approach 2:
The mechanism nests multiple components within each other: the plunger is housed within the slider, which contains the rollers, which in turn interact with the ramp surfaces. This nested arrangement achieves compactness without significantly increasing structural complexity
4Reliability
If an existing seal design is used, then basic sealing is achieved, but the mechanism is not compact and occupies excessive space
Solution Approach 1:
The patent nests the plunger within the slider housing, and positions the rollers within the space between the slider and mounting plate. This nested configuration achieves compactness by utilizing the available space efficiently, reducing the overall volume occupied by the seal mechanism while maintaining reliable sealing function
Solution Approach 2:
The mechanism transforms lateral motion of the slider into vertical motion of the drop-plate through the ramp surfaces. This dimensional transformation allows the seal to achieve its full sealing stroke in a compact lateral space, reducing the volume required for the mechanism
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 a compact, efficient, and adjustable seal that minimizes friction and wear, effectively closing the door gap with reduced force requirements, suitable for security, weather, flood, RF, and acoustic applications, while accommodating various door widths and bolting systems.
Implementation Method 1
The first rollers, which are pushed by the ramp surfaces, are provided to reduce friction and so reduce the force required to extend the drop-plate. The rolling action of the first rollers against the ramp surfaces also reduces wear
Implementation Method 2
As well as guiding the lateral motion of the slider, the second rollers also reduce friction acting against movement of the slider
Data Source
AI summary
A movable seal for mounting to a door, the moveable seal including a drop-plate configured to move to close or cover a gap between a bottom of a door and a floor, a plunger extending laterally configured to be pressed by a door frame as the door closes, a slider arranged to be moved laterally by the plunger when the plunger is pressed, the slider having one or more ramp surfaces, and one or more first rollers. The slider is configured such that when pushed laterally by the plunger the one or more ramp surfaces push against the one or more first rollers moving the drop-plate transversely to extend the drop plate outwards for closing or covering the gap to the floor.