Sectional Door Lifting Mechanism with Segmented Torsional Spring
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Solution Overview
Problem
Existing door lifting mechanisms for sectional doors are complex, bulky, and difficult to install, posing safety risks and requiring significant power for operation, especially when handling heavy or fireproof doors, and are not easily adaptable to ceiling-mounted installations.
Innovation Solution
A simplified door lifting mechanism with a gear system and torsional spring that uses snub pulleys and adjustable cables, allowing for easy assembly, quick preload adjustment, and reduced size, enabling installation by one person and ensuring safety from potential component failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional balancing systems with shafts, drums, and torsional springs are used, then the door weight can be balanced during operation, but the device becomes complex and bulky, making installation difficult and time-consuming
Solution Approach 1:
The traditional integrated balancing system is segmented into separate functional elements: the torsional spring remains mounted on the shaft for weight balancing, while the cable attachment and tensioning mechanisms are separated and made independently adjustable. This segmentation allows each component to be simplified and adjusted without affecting the others, reducing overall system complexity while maintaining the door balancing function.
Solution Approach 2:
The invention introduces dynamic adjustability to the cable system, allowing the cable attachment points and tension to be modified during installation and operation. This dynamic capability replaces the need for complex pre-calibration mechanisms, enabling installers to adapt the system to different door weights and configurations without requiring complex adjustment procedures or specialized tools.
2Reliability
If traditional balancing systems are used, then the door can be balanced, but the device requires considerable installation space and height from the floor, making it difficult to install in standard garage configurations
Solution Approach 1:
The invention repositions the cable attachment system from a horizontal arrangement (requiring wide clearance and height from the floor) to a vertical arrangement along the door panels and tracks. By utilizing the vertical dimension of the door assembly rather than requiring horizontal space, the system achieves the same balancing function while fitting within standard garage door configurations with limited installation clearance.
3Reliability
If traditional balancing systems with preloaded springs are used, then the door weight can be balanced, but the installer is exposed to safety risks during preload calibration due to heavy loads on components
Solution Approach 1:
The system allows the torsional spring to be preloaded and secured to the shaft before the door is installed, with the spring ends initially held in a safe, non-load-bearing position. The cable attachment to the door occurs after the spring is safely mounted, allowing the spring to gradually take up load as the door is raised. This preliminary action separates the dangerous spring loading operation from the door installation, protecting the installer from sudden releases or component failures under full door weight.
Solution Approach 2:
The invention incorporates safety features such as cable tensioners with controlled release mechanisms and spring ends that can be initially positioned in a low-energy state. These cushioning elements are built into the system design to prevent catastrophic failure if a component breaks under load, allowing the installer to work safely without being directly in the path of potentially failing components while still achieving the necessary door balancing.
4Reliability
If heavy-duty components are used for fireproof or reinforced doors, then the door weight can be balanced, but the weight of the lifting system components increases, making installation even more difficult
Solution Approach 1:
The invention uses adjustable cable tensioning mechanisms that allow the system to adapt to different door weights without requiring different component specifications. By enabling continuous adjustment of cable tension and attachment points, the same lifting system can accommodate both lightweight sectional doors and heavy fireproof doors, eliminating the need for heavier-duty components for reinforced doors while maintaining adequate balancing capability through parameter adjustment rather than component substitution.
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 mechanism facilitates easy and safe installation of sectional doors with reduced dimensions, enabling efficient operation and cost-effective manufacturing, while ensuring installer safety and ease of use, even in challenging configurations like garages.
Implementation Method 1
a shaft provided with a pair of drums, each drum being fixed at one shaft end, and two pairs of plates fixed on the shaft in symmetric positions in respect of its central section. In the space between each pair of plates, a torsional spring is wound on the shaft
Implementation Method 2
Around each drum, cables are wound, one end of the cable being connected to the door or to a panel of the door
Data Source
Figure 1~1a
Figure 2
Figure 3~3A
AI summary
The present invention discloses a mechanism (100) particularly suitable for use with lifting systems of sectional doors comprising at least a pair of independent main bodies (120), each provided with a cavity (190) and conjugate profiles (130) operatively associated with one another formed on a portion of lateral surface of said main bodies (120). The remaining portion (140) of said lateral surface of said main bodies (120) is arranged for winding of lifting cables of said lifting systems; there is also a rotating shaft (150) for each main body (120) housed in said cavity (190); an elastic member (170) connected to said shaft (150) and to a surface (192) of said cavity (190); and an overrunning mechanism (180) operatively connected with said shaft (150). The disclosed mechanism more particularly comprises an elastic member (170) which is under full load when the sectional door is closed, and is fully released when the sectional door is fully open, and the relief curve of said elastic member (170) is proportional to the weight vertically exerted by said sectional door, said weight being variable along the vertical during the lifting operation of the door, the weight of the already lifted door portion being supported by horizontal guides (230) and no longer by said elastic member (170).