Large Screen Display Drum Drive Mechanism for Axle Twist Prevention
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Solution Overview
Problem
Large screen displays face issues with axle twisting and cable snarling during winding and unwinding, due to the high weight and length of the screens, and the use of slip ring connectors for electrical cables leads to unacceptable results.
Innovation Solution
A rotatable drum with a truss structure and a driven sprocket system that applies winding force outwardly of the axle axis, combined with a cable assembly that spirals around the axle to prevent twisting and snarling, and a non-sliding connection for the electrical cable.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the winding force is applied directly to the axle, then the screen can be wound up, but the axle may twist causing delayed movement, jamming, and eventual failure
Solution Approach 1:
The patent introduces a drum component that changes the dimension of force application. Instead of applying winding force directly along the axle axis, the force is applied to the drum's outer periphery, creating a torque that is then transmitted to the axle through the drum's rotation. This dimensional change prevents direct axial loading that causes twisting.
Solution Approach 2:
The drum acts as an intermediary between the winding force and the axle. The force is first applied to the drum, which then converts it to rotational motion that drives the axle. This intermediary mechanism protects the axle from direct twisting forces while still enabling effective winding.
2Reliability
If a slip ring type of cable connector is used, then electrical connection is maintained during rotation, but unacceptable results are obtained due to high frequency data transmission
Solution Approach 1:
The patent extracts the cable connection from the rotating drum system by routing it through the central axle hole. The cable remains stationary while the drum rotates around it, eliminating the need for slip rings and their associated electrical interference problems with high-frequency data transmission.
3Loss of information
If a non-sliding connection is used for the cable, then data transmission quality is maintained, but the cable may twist during rotation of the wind-up drum
Solution Approach 1:
The cable is routed through the central axle hole, changing its spatial arrangement from the drum's outer periphery to its rotational axis. This dimensional repositioning allows the cable to remain stationary while the drum rotates around it, preventing twisting and maintaining both data transmission quality and cable stability.
4Device complexity
If the driver motor is located along the same axis as the wind up mechanism, then the structure is compact, but the axle twisting problem occurs
Solution Approach 1:
The drive mechanism is positioned at the drum's outer periphery rather than along the central axle axis. This spatial reconfiguration allows the motor to apply torque to the drum without creating axial twisting forces on the axle, resolving the contradiction between structural simplicity and reliability.
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 prevents axle twisting and cable snarling, allowing for smooth extension and retraction of large screen displays while maintaining a fixed external connection for the cable, effectively managing the weight and winding forces.
Implementation Method 1
A drum upon which the large screen display is mounted includes an axle that has opposite ends rotatably mounted to a pair of bearing
Implementation Method 2
The cable assembly is wrapped around an outer portion of the axle that is located outwardly from the drum thereby preventing the cable assembly from snarling as the drum is rotated
Implementation Method 3
providing a mechanical advantage. Disclosed herein is a drum surrounding the wind up axle with the wind up force being applied through the drum outwardly of the axle eliminating axle twisting, and also providing a mechanical advantage when winding the drum
Data Source
AI summary
A large screen display drive mechanism. A drum is rotatably mounted to a truss by an axle that extends centrally through the drum and mounted by bearings, in turn, mounted to the truss. A large screen display is wrappable on the drum and is electrically connected by a cable assembly extending through the drum and outwardly thereof through a sprocket fixedly mounted to an end of the drum. The cable assembly is wrapped around a portion of the axle extending outwardly of the drum. A motor with sprocket and chain drives the sprocket attached to the drum.