Tilt-Up Door Cam Mechanism for Wide Opening Sag
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Solution Overview
Problem
Conventional sectional overhead doors are not suitable for door openings wider than eight feet due to sagging issues and structural integrity concerns, particularly in large buildings where wind loads and equipment movement are significant.
Innovation Solution
A tilt-up door system with a door frame comprising vertical columns, roller assemblies, and a cam mechanism that allows the door to pivot from a vertical closed position to a horizontal open position, using cams and cam followers to guide the door's movement and maintain structural stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If conventional sectional overhead doors are used for wide openings, then the door can be opened, but the door panels sag in the middle due to span issues
Solution Approach 1:
The door is divided into multiple horizontal sections that can move independently. Each section is supported by its own set of rollers and structural elements, allowing the door to be opened without requiring the entire large panel to be rigid. This segmentation prevents sagging by distributing the load across multiple smaller, more stable sections.
Solution Approach 2:
The door system transitions from a single-plane rigid structure to a multi-dimensional system with vertical columns, horizontal beams, and roller assemblies operating in multiple planes. The cam mechanism introduces a curved motion path that moves the door through vertical and horizontal components, adding dimensional complexity to prevent sagging while enabling wide opening clearance.
2Stability of the object's composition
If a single panel door with truss is used, then sagging is prevented, but the door cannot freely open in wide openings
Solution Approach 1:
The door system uses dynamic roller assemblies that move along vertical columns during operation. The rollers transition from supporting the door in a closed vertical position to allowing horizontal movement during opening. The cam mechanism provides dynamic guidance, changing the door's motion path from vertical to horizontal as opening progresses, enabling free movement without compromising stability.
Solution Approach 2:
The roller assemblies act as intermediary elements between the door panels and the building structure. These rollers mediate the interaction by providing temporary support during the opening transition, allowing the door to move freely while maintaining structural integrity. The cam mechanism serves as an intermediary guide that coordinates the complex motion between door sections and support columns.
3Area of stationary object
If the door is made larger for wide openings, then the opening can be closed properly, but more steel is required in the building frame
Solution Approach 1:
The structural support system uses local quality by concentrating strength where needed. Vertical columns are positioned at specific locations to bear the door's weight and resist wind loads, while horizontal beams provide localized support at critical points. This distributed local reinforcement allows large door openings without requiring uniform thickening of the entire building frame, reducing overall steel consumption.
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
Enables the use of tilt-up doors in wider openings by preventing sagging and ensuring structural soundness, allowing for efficient movement of large equipment and materials while reducing steel requirements in the building frame.
Implementation Method 1
a roller assembly as well as roller assembly supports
Implementation Method 2
first and second cams, each connected to one of the at least two vertical side members of said tilt-up door
Data Source
AI summary
A tilt-up door having vertical side members each having a pivot point, the pivot points move upward or downward when an actuator is activated to move the door between open and closed positions. First and second cams connected to the vertical side members at a lower end of the cams, each of said cams extend from the lower end thereof upwardly and arcuately toward an interior of a building to a distal terminal end thereof, each of the ends contacts a cam follower. The cam followers slide along the first and second cams and guide the first and second cams and the door as the door moves between the open and closed positions.